Next Article in Journal
Adsorption Behaviors of ctDNA and Biological Activities Based on Polyvinyl Alcohol/Polyethylene Glycol/Quaternized Chitosan Composite Hydrogel
Next Article in Special Issue
Tin Disulfide Nanosheet as Cathode Materials for Rechargeable Aluminum Ion Batteries: Synthesis, Electrochemical Performance, and Mechanism
Previous Article in Journal
Quality Characteristics and Volatile Components of Chili Oil Prepared from the Combination of Shuanla and Erjingtiao Peppers
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Molecules
Volume 29
Issue 23
10.3390/molecules29235768
molecules-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

Rational Design of Novel Single-Atom Catalysts of Transition-Metal-Doped 2D AlN Monolayer as Highly Effective Electrocatalysts for Nitrogen Reduction Reaction

by
Xiaopeng Shen
1,* and
Qinfang Zhang
2,*
1
School of Chemistry & Chemical Engineering, Yancheng Institute of Technology, Yancheng 224051, China
2
School of Materials Science and Engineering, Yancheng Institute of Technology, Yancheng 224051, China
*
Authors to whom correspondence should be addressed.
Molecules 2024, 29(23), 5768; https://doi.org/10.3390/molecules29235768
Submission received: 14 November 2024 / Revised: 2 December 2024 / Accepted: 5 December 2024 / Published: 6 December 2024
(This article belongs to the Special Issue Advances in 2D Materials for Electrochemical Applications)
Browse Figures
Review Reports Versions Notes

Abstract

:
The single-atom catalysts (SACs) for the electrocatalytic nitrogen reduction reaction (NRR) have garnered significant attention in recent years. The NRR is regarded as a milder and greener approach to ammonia synthesis. The pursuit of highly efficient and selective electrocatalysts for the NRR continues to garner substantial interest, yet it poses a significant challenge. In this study, we employed density functional theory calculations to investigate the stability and catalytic activity of 29 transition metal atoms loaded on the two-dimensional (2D) AlN monolayer with Al monovacancy (TM@AlN) for the conversion of N2 to NH3. After screening the activity and selectivity of NRR, it was found that Os@AlN exhibited the highest activity for NRR with a very low limiting potential of −0.46 V along the distal pathway. The analysis of the related electronic structure, Bader charge, electron localization function, and PDOS revealed the origin of NRR activity from the perspective of energy and electronic properties. The high activity and selectivity towards the NRR of SACs are closely associated with the Os-3N coordination. Our findings have expanded the scope of designing innovative high-efficiency SACs for NRR.

1. Introduction

Ammonia (NH3) not only plays an indispensable role in agriculture and chemical industry for human society [1,2,3] but also serves as a carbon-free hydrogen carrier due to its high hydrogen mass fraction (17.6 wt%) [4]. In the natural nitrogen cycle, the production of NH3 can occur through biological fixation of N2 by nitrogenase enzymes in bacteria, or through lightning-induced nitrogen fixation in the atmosphere. While in the traditional industrial synthetic NH3 industry, the Haber–Bosch (H-B) process is normally catalyzed within the Fe- or Ru-based catalysts under high temperature and pressure (700 K and 100 bar) react conditions [5], it consumes a massive quantity of fossil fuels and releases substantial amounts of carbon dioxide, thus causing energy crisis and serious environmental problems [6]. So, developing an environmentally friendly and cost-effective alternative to the Haber–Bosch process for NH3 production is a pressing task.
In recent years, the electrocatalytic nitrogen reduction reaction (eNRR) under ambient conditions has aroused the extensive interest of researchers [7,8,9,10,11,12,13,14]. The stable and efficient catalysts are crucial for eNRR as they help in reducing the energy barrier of the reaction. Among the diverse range of catalysts, single-atom catalysts (SACs) are emerging as the most promising. SACs process excellent catalytic stability, selectivity, and activity due to the strong electronic interaction between the single atom and the substrate. Currently, SACs have been widely applied in numerous important electrochemical catalytic reactions such as the NRR [10,11,12,13,14], the CO2 reduction reaction (CO2RR) [15,16,17,18], the oxygen reduction reaction (ORR) [19,20,21], the hydrogen evolution reaction (HER) [22,23,24,25], and the oxygen evolution reaction (OER) [26,27,28,29].
Many SACs composed of two-dimensional (2D) materials serve as the substrate for anchoring transition metal (TM) atoms and have been extensively studied for eNRR, such as TM@BN [30,31], TM@h-C3N4 [32], TM/g-C9N10 [12], TM-graphyne [33], TM@B36 [34], TM@MoSe2 [11], TM@BP [35,36], etc. These TM-SACs studies have proved that the empty d orbitals of TM atoms would accept the lone pair electrons of N2, while the electrons from TM-atom-occupied d-orbitals would be back-donated to the empty antibonding orbitals of N2, forming the “σ-donation and π-back-donation” electron transfer mechanism. However, the catalytic performance of the above-reported SACs is significantly inferior to that of traditional thermal ammonia synthesis catalysts, and it is still a long way from practical large-scale application. Moreover, metal atoms tend to migrate and aggregate to form metal nanoclusters while doped on the surface of the support, which would result in catalyst deactivation. Therefore, it is crucial to identify appropriate substrates that can provide TM-N coordinate sites to accommodate single TM atoms, improving the NRR performance of SACs.
The aluminum nitride (AlN) monolayer has been widely investigated, and it can be applied to high-power, high-temperature, and high-frequency electronic devices due to its broadband gap and high chemical and thermal stability [37]. To date, Zhang et al. have searched more than a dozen transition metal (TM)-doped AlN systems for HER/OER/ORR electrocatalysts based on first-principles calculations. They found that Co@AlN-VAl can be available as OER/ORR bifunctional catalysts with an ηOER/ηORR of 0.5/0.33 V, and Pd@AlN-VAl shows the highest HER catalytic activity with an ηHER of 0.009 V [38]. Wang et al. theoretically designed a bilayer tetragonal AlN monolayer as the Li-O2 electrochemical catalyst [39]. AlN monolayer and SiC emerge as promising catalysts for formic acid (HCOOH) production in CO2RR [40]. The above-reported studies have demonstrated that AlN nanomaterials have great potential value in the field of electrocatalysis, but there has been no relevant literature about AlN catalysts towards NRR until now.
Here, in this work, we introduce 29 kinds of TM atoms into the AlN monolayer with Al vacancy and systematically investigate the stability, catalytic activity, pathways, and selectivity of NRR using density functional theory (DFT) calculation. The Os@AlN SAC are screened out, and the theoretical limiting potentials are calculated to be −0.46 V by a distal mechanism. We further analyzed the electronic properties, electron transfer, electron localization function, and PDOS to explore the origin of the exceptional NRR performances. This work will provide theoretical guidance for designing advanced AlN-based materials for NH3 synthesis.

2. Computational Details

In this paper, the Vienna Ab initio Simulation Package (VASP) [41,42] is utilized to carry out all spin-polarized energy and structure optimization calculations. The Projector Augmented Wave (PAW) method is employed to delineate the electron–ion interactions [43,44]. The interaction between ions and electrons is illustrated using the Perdew–Burke–Ernzerh (PBE) functional within the generalized gradient approximation (GGA) [42]. The long-range van der Waals interaction between the adsorbates and the substrates is evaluated by the DFT-D3 method [45]. A vacuum space of 15 Å along the z-direction is added to sufficiently avoid interactions between periodic layers. For the structural optimization, the 4 × 4 supercell of AlN monolayer containing 32 atoms is constructed, in which the kinetic cutoff energy of the plane wave function is set as 450 eV, the convergence threshold of the energy and force are 10−5 eV and 0.02 eV/Å, respectively. The Brillouin zone is sampled by 3 × 3 × 1 and denser 21 × 21 × 1 Monkhorst–Pack (MP) grid during structural optimization and electronic properties calculations.
The binding energy (Eb) can be calculated using the following equation:
Eb = ETM@AlN − EAlN − ETM
where ETM@AlN is the total energy of the TM supported on the AlN monolayer, and EAlN and ETM are the energies of the AlN monolayer and a single TM atom, respectively.
The adsorption energy (Eads) of reaction intermediates on the TM@AlN catalysts can be calculated as follows:
Eads = Etotal − ETM@AlN − Eadsorbate
where Etotal is the total energy of the adsorbate and TM@AlN species, and ETM@AlN and Eadsorbate are the energies of TM@AlN and the free adsorbate, respectively. All energies were calculated with the same parameter settings. By definition, a negative Eb and Eads value means that the adsorption is exothermic.
The changes in Gibbs free energy (ΔG) of each hydrogenation step in the NRR process were calculated by using the computational hydrogen electrode (CHE) model developed by Nørskov and co-workers [46], and ΔG could be determined as follows:
ΔG = ΔE + ΔEZPE − TΔS + ΔGU + ΔGpH
where ∆E is the reaction energy between the difference adsorption states of the intermediates, and ΔEZPE and ∆S are the changes in zero-point energies and entropy during the reaction, respectively. T is the temperature of 298.15 K. ΔGU is the contribution of the applied electrode potential (U) to ΔG, respectively. ΔGpH is the correction of free energy for H+, which was described by ΔGpH = ln10 × kBT × pH, and kB is the Boltzmann constant under standard reaction conditions (pH = 0, 298.15 K, 101,325 Pa). The ΔG values can be obtained from VASPKIT (https://vaspkit.com) [47]. The entropies of the gas molecules (i.e., H2, N2, and NH3) were taken from the NIST database.
The limiting potential (UL) was defined as UL = −ΔGmax/e, where ΔGmax is the maximum positive value of ΔG. UL was the smallest applied negative potential to keep every elemental step becomes spontaneous. Therefore, it was utilized to assess the intrinsic NRR activity of catalysts. Ab initio molecular dynamics (AIMD) simulations were performed to evaluate the thermodynamic stability of the catalyst.

3. Results and Discussion

3.1. Screening of TM@AlN SACs as NRR Electrocatalysts

Firstly, we calculated the structures of the 4 × 4 × 1 supercell of the AlN monolayer anchoring the N2 molecule with end-on and side-on configurations. As illustrated in Figure 1 and Table S1, the two structures have small negative adsorption energies (−0.093 eV and −0.083 eV) and large Al-N distances (2.727 Å, 3.586 and 3.537 Å between the AlN and N2 molecule, suggesting that the pristine 2D AlN monolayer is not suitable for electrocatalysis NRR. Therefore, we select the one Al-atom-defective AlN monolayer to anchor a single 3d, 4d, and 5d TM atom to construct the SACs candidates for catalyzing the NRR.
Then, after fully optimized without any constraints, the calculated binding energies of these 29 different SACs are listed in Figure 1b–d. The nonmagnetic (NM) and the ferromagnetic (FM) spin polarization have been involved in our calculation of the system energy. Our calculations show that the magnetic moments resulting from spin polarization mainly localize on the TM (Table S2). The results show that most of the TM@AlN SACs are quite thermodynamically stable, while the Y@AlN is poorly stable, so this system is unsuitable as an electrocatalyst and will not be studied subsequently. It is worth mentioning that these large negative binding energies (ranging from −4.89 to −15.91 eV) are mainly due to the sp2 orbital hybridization of the N atom. Previous studies have shown that the entire NRR process comprises six intricate hydrogenation reaction steps with two types of N2 molecule adsorption models (end-on and side-on patterns) [1,48,49], and the free energy change in the first protonation (ΔG(*N2–*NNH)) or last protonation steps (ΔG(*NH2–*NH3)) exhibited the highest ΔG values among the various NRR pathways. We could use the screening criteria that both the values of the free energy change in the first protonation (ΔG(*N2–*NNH)) or last protonation steps (ΔG(*NH2–*NH3)) should be less than 0.49 eV for the extensive screening of highly active NRR catalysts [49]. The calculated ΔG(*N2–*NNH) and ΔG(*NH2–*NH3) of TM@AlN systems are shown in Figure 2. The results indicate that only the Os@AlN catalyst fulfilled the necessary criteria, and thus, it was subjected to further investigation and discussion.

3.2. NRR Mechanisms and Selectivity on Os@AlN

According to recently reported references [50,51,52,53,54], there exist four common NRR mechanisms, namely the distal, alternating, consecutive, and enzymatic reaction pathways. The distal and alternating pathways originate from N2 molecule end-on adsorption patterns, whereas the pathways of consecutive and enzymatic commence from N2 molecule side-on adsorption patterns (Figure S2a). The optimized structures of the intermediates for each elementary reaction step in the four NRR reaction pathways are presented in Figure 3 and Figure 4. The Gibbs free energy diagrams of NRR processes on Os@AlN are presented in Figure 5. The limiting potential (UL) represents the minimum energy needed for NRR, which is determined by the potential determining step (PDS) with the highest ΔG among all reaction steps. The smaller the UL, the smaller the overpotential and energy barrier. Therefore, the corresponding reaction pathway is deemed as the optimal one, favoring the NRR process.
As displayed in Figure 5a,b, the last hydrogenation reaction can be viewed as the PDS of the distal pathway of NRR on Os@AlN. For the alternating pathway, the PDS is the second hydrogenation reaction. And the corresponding UL are −0.46 V and −0.84 V, respectively. For the consecutive pathway of the Os@AlN catalyst, the most positive Gibbs free energy change (ΔGmax) in the *N-*NH3→*NH reaction step with UL of −0.77 V (Figure 5c). Along the enzymatic pathway, the PDS is the third hydrogenation reaction step with UL = −0.86 V (Figure 5d). In brief, the Os@AlN is predicted to be a high-activity NRR electrocatalyst with a lower UL value of −0.46 V through the distal pathway.
The selectivity of the Os@AlN catalyst is also evaluated by considering the competitive reaction of HER. An ideal catalyst for NRR is one that can effectively inhibit the HER. As depicted in Table S3, the value of Δ G * N 2 (end on) (−0.074 eV) is more negative than the value of Δ G * H (−0.042 eV), which infers that the N2 molecule is preferentially adsorbed on the catalyst than the H atom. This implies that the Os@AlN catalyst exhibits excellent NRR selectivity.

3.3. Origin of High NRR Catalytic Activity of Os@AlN

To explore the mechanism of catalytic activity from the perspective of electronic properties of Os@AlN, calculations of the density of states (DOS) and Bader charge analysis were performed. When compared with the DOS of free N2 (Figure 6a), the N2 molecule adsorbs on the Os@AlN catalyst with end-on adsorption pattern. This causes the antibonding state of N2 to split and hybridize with the Os-d orbital, resulting in occupied orbitals below the Fermi level (Ef) and unoccupied antibonding states above Ef. Figure 6c,d displays the PDOS before and after N2 adsorption on Os@AlN, with the Os-d and N-p orbitals marked in purple and blue, respectively. It can be clearly seen that the N-p orbital and the Os-d orbital are remarkably overlapped around the Ef. This is attributed to the “acceptance–donation” mechanism [55], which is that the empty d orbitals of TM receive the lone-pair electrons from N2 and simultaneously donate the d orbital electrons back to the antibonding orbitals of N2. As a result, the inert N≡N bond is activated, making subsequent hydrogenation steps easier.
Furthermore, Figure S3 (Supplementary Materials) illustrates the band structures of pristine AlN, defective AlN with Al monovacancy, Os@AlN, and N2 adsorption on Os@AlN with end-on configuration. The pristine AlN is a semiconductor with an indirect band gap of 2.93 eV (Figure S3a, Supplementary Materials), which is smaller than the experimental value of 6.2 eV [56]. The outcome is widely recognized that DFT calculations tend to underestimate the semiconductor band gaps. While creating the monovacancy AlN, the original large band gap reduces to a small one (0.44 eV) (Figure S3b, Supplementary Materials). After the N2 adsorption on Os@AlN with end-on configuration, the band gap decreases from 1.22 eV (Figure S3c, Supplementary Materials) to 0.23 eV (Figure S3d, Supplementary Materials). This is due to the new Os-N bond being formed between the N2 molecule and the Os@AlN. To gain a deeper understanding of the interaction between the single Os atom and its neighboring N atoms, electron localization function (ELF) analysis was performed for Os@AlN and N2 adsorbed on Os@AlN with end-on configuration systems. In general, a high ELF value denotes a covalent bond type between atoms, while a lower ELF value indicates an ionic bond. It can be clearly seen from Figure 7a that when Os is anchored in the Al vacancy of the AlN monolayer, there is weaker electron localization between Os and its surrounding three N atoms, indicating the formation of the Os-N ionic bonds. After adsorbing the N2 molecule, a stronger electron localization between Os and its neighboring N atom can be found in Figure 7b, suggesting that fewer electrons are transferred from the N atom to Os and more electrons are transferred from the N2 molecule to Os.
Figure 8a illustrates the charge transfer of each component of Os@AlN SAC along the distal pathway, where the SAC system is divided into three moieties: the AlN substrate (moiety 1), the catalytic active center of Os atom and its three neighboring N atoms (moiety 2), and the NxHy intermediates (moiety 3). Noticeably, a large number of electrons are transferred from the AlN substrate (moiety 1) to the NxHy intermediates (moiety 3) through the Os-N3 active site (moiety 2). This indicates the AlN substrate serves as a significant source of electrons, while the Os-N3 active site can be regarded as the electronic transmitter. Figure 8b shows the differential charge density of N2 adsorbed on Os@AlN with end-on adsorption configuration. It reveals the accumulation and depletion of electrons at both the reactive site and the N2 molecule, indicating a bidirectional electron transfer between the TM atom and N2. The Bader charge analysis reveals that 0.41 e− are transferred from Os@AlN to N2, effectively activating N2 and facilitating the subsequent hydrogenation process. At last, we conducted the ab initio molecular dynamics (AIMD) simulation at 350 K for 10 ps with a time step of 2 fs using a Nosé–Hoover thermostat to check the thermal stability of the Os@AlN system. Figure S4a presents the variations in temperature and energy with time for Os@AlN. It has been observed that the temperature fluctuates slightly around 350 K, and the energy varies within a narrow range. Figure S4b demonstrates that the geometric structure of the Os@AlN catalyst is well-preserved, with no evident structural distortion or collapse, thereby indicating its reliable thermodynamic performance.

4. Conclusions

In summary, we systematically investigated the SACs model of a single transition metal atom loaded on the AlN monolayer (TM@AlN) as the potential NRR electrocatalyst using DFT calculations. After calculating the N2 adsorption energies and activation and evaluating the reaction mechanism of the NRR process and selectivity between HER and NRR, Os@AlN is selected as a highly active NRR catalyst with a limiting potential of −0.46 V through the distal mechanism. The density of states, charge transfer, differential charge density, and electron localization function are utilized to uncover the source of NRR activity in Os@AlN. The AIMD simulation demonstrates that Os@AlN is thermodynamically stable. Our results indicate that AlN-based nanomaterials hold significant promise as an NRR electrocatalyst. This work offers novel insights for the rational design of effective SACs for NRR.

Supplementary Materials

The following supporting information can be downloaded at https://www.mdpi.com/article/10.3390/molecules29235768/s1, Figure S1. Top and side view of the optimized geometric structures of the adsorption of N2 on pristine AlN monolayer with the (a) end-on and (b) side-on patterns. Figure S2. (a) The geometric structures of the adsorption of N2 on TM@AlN via the end-on and side-on configures. Adsorption energy (Eads in eV) of N2 adsorbed on (b) 3d TM@AlN, (c) 4d TM@AlN and (d) 5d TM@AlN. Figure S3. The pristine AlN monolayer (a), defective AlN with Al monovacancy (b), Os@AlN (c) and N2 adsorption on Os@AlN with end-on configuration (d) of top view and side view, and the corresponding band structures (DFT-PBE level). The black and red dotted lines in the band structures denote the spin-up (↑) and spin-down (↓) channels, respectively. The Fermi-level is set to be zero denoted by green dash line. The orange, blue, and gray denote Al, N, and Os atoms, respectively. Figure S4. (a) The temperature and energy fluctuations of Os@AlN during 10 ps of AIMD simulation with a time step of 2 fs. (b) The top and side views of Os@AlN after 10 ps of AIMD simulation at T = 350 K. Table S1. Calculated adsorption energies values of N2 on pristine AlN monolayer with the end-on and side-on patterns. Table S2. The relative energies (ΔE) of nonmagnetic (NM) and the ferromagnetic (FM) spin polarization, the magnetic moments of FM (Mtot) of the different SACs. Table S3. Calculated Δ G * H and Δ G * N 2 values of Os@AlN with end-on and side-on adsorption configurations.

Author Contributions

X.S. and Q.Z. conceived the research and were responsible for the selection of the methodology and software; X.S. conducted the theoretical calculation and analyzed the conclusion; Q.Z. was responsible for data curation; X.S. and Q.Z. drafted the paper. All authors contributed equally to writing, reviewing, and editing the manuscript. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The original contributions presented in this study are included in the article/Supplementary Materials. Further inquiries can be directed to the corresponding authors.

Acknowledgments

The authors acknowledge support from the National Natural Science Foundation of China (No. 12474276 and 12274361) and school-level research projects of Yancheng Institute of Technology (xjr2020043). The authors also acknowledge the Beijing PARATERA Tech Co., Ltd. (https://www.paratera.com/) for supercomputer time.

Conflicts of Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

References

  1. Li, L.; Wang, X.Y.; Guo, H.R.; Yao, G.; Yu, H.B.; Tian, Z.Q.; Li, B.H.; Chen, L. Theoretical screening of single transition metal atoms embedded in MXene defects as superior electrocatalyst of nitrogen reduction reaction. Small Methods 2019, 3, 1900337. [Google Scholar] [CrossRef]
  2. Qing, G.; Ghazfar, R.; Jackowski, S.T.; Habibzadeh, F.; Ashtiani, M.M.; Chen, C.P.; Smith, M.R.; Hamann, T.W. Recent advances and challenges of electrocatalytic N2 reduction to ammonia. Chem. Rev. 2020, 120, 5437–5516. [Google Scholar] [CrossRef] [PubMed]
  3. Yang, B.; Ding, W.L.; Zhang, H.H.; Zhang, S.J. Recent progress in electrochemical synthesis of ammonia from nitrogen: Strategies to improve the catalytic activity and selectivity. Energy Environ. Sci. 2021, 14, 672–687. [Google Scholar] [CrossRef]
  4. Huang, Z.; Rafiq, M.; Woldu, A.R.; Tong, Q.X.; Astruc, D.; Hu, L. Recent progress in electrocatalytic nitrogen reduction to ammonia (NRR). Coord. Chem. Rev. 2023, 478, 214981. [Google Scholar] [CrossRef]
  5. Chu, K.; Liu, Y.P.; Li, Y.B.; Wang, J.; Zhang, H. Electronically Coupled SnO2 Quantum Dots and Graphene for Efficient Nitrogen Reduction Reaction. ACS Appl. Mater. Inter. 2019, 11, 31806–31815. [Google Scholar] [CrossRef]
  6. Ma, L.; Xu, F.; Zhang, L.; Nie, Z.; Xia, K.; Guo, M.; Li, M.; Ding, X. Breaking the linear correlations for enhanced electrochemical nitrogen reduction by carbon-encapsulated mixed-valence Fe7(PO4)6. J. Energy Chem. 2022, 71, 182–187. [Google Scholar] [CrossRef]
  7. Zhao, X.; Hu, G.; Chen, G.F.; Zhang, H.; Zhang, S.; Wang, H. Comprehensive understanding of the thriving ambient electrochemical nitrogen reduction reaction. Adv. Mater. 2021, 33, 1–10. [Google Scholar] [CrossRef]
  8. Zhao, Y.C.; Yan, L.T.; Zhao, X.B. Development of carbon-based electrocatalysts for ambient nitrogen reduction reaction: Challenges and perspectives. Chem. Electro. Chem. 2022, 9, 1–15. [Google Scholar] [CrossRef]
  9. Wu, B.; Lin, Y.C.; Wang, X.Z.; Chen, L. Recent advances on electrocatalytic fixation of nitrogen under ambient conditions. Mater. Chem. Front. 2021, 5, 5516–5533. [Google Scholar] [CrossRef]
  10. He, C.; Ma, J.L.; Wu, Y.B.; Zhang, W.X. Design of novel transition-metal-doped C4N4 as highly effective electrocatalysts for nitrogen fixation with a new intrinsic descriptor. J. Energy Chem. 2023, 84, 131–139. [Google Scholar] [CrossRef]
  11. Hou, P.F.; Huang, Y.H.; Ma, F.; Zhu, G.Q.; Du, R.A.; Wei, X.M.; Zhang, J.M.; Wang, M. Screening of single-atom catalysts of transition metal supported on MoSe2 for high-efficiency nitrogen reduction reaction. Mol. Catal. 2023, 537, 112967. [Google Scholar] [CrossRef]
  12. Wang, M.; Huang, Y.; Ma, F.; Zhu, G.; Zhang, J.; Wei, X.; Hou, P.; Du, R.; Liu, J. Theoretical insights into the mechanism of nitrogen-to-ammonia electroreduction on TM/g-C9N10. Mol. Catal. 2023, 547, 113391. [Google Scholar] [CrossRef]
  13. Zhang, S.; Lu, S.; Zhang, P.; Tian, J.; Shi, L.; Ling, C.; Zhou, Q.; Wang, J. Accelerated discovery of single-atom catalysts for nitrogen fixation via machine learning. Energy Environ. Mater. 2023, 6, e12304. [Google Scholar] [CrossRef]
  14. Lin, X.; Wang, Y.; Chang, X.; Zhen, S.; Zhao, Z.J.; Gong, J. High-throughput screening of electrocatalysts for nitrogen reduction reactions accelerated by interpretable intrinsic descriptor. Angew. Chem. Int. Ed. Engl. 2023, 62, e202300122. [Google Scholar] [CrossRef]
  15. Tan, X.; Tahini, H.A.; Smith, S.C. Defect engineering in graphene-confined single atom iron catalysts for room temperature methane conversion. J. Phys. Chem. C 2021, 125, 12628–12635. [Google Scholar] [CrossRef]
  16. Ju, L.; Tan, X.; Mao, X.; Gu, Y.; Smith, S.; Du, A.; Chen, Z.; Chen, C.; Kou, L. Controllable CO2 electrocatalytic reduction via ferroelectric switching on single atom anchored In2Se3 nanosheets. Nat. Commun. 2021, 12, 5128. [Google Scholar] [CrossRef]
  17. Kour, G.; Mao, X.; Du, A. Computational screening of transition metal phthalocyanines for the electrochemical reduction of carbon dioxide. J. Phys. Chem. C 2020, 124, 7708–7715. [Google Scholar] [CrossRef]
  18. Gao, D.; Zhang, Y.; Zhou, Z.; Cai, F.; Zhao, X.; Huang, W.; Li, Y.; Zhu, J.; Liu, P.; Yang, F. Enhancing CO2 Electroreduction with the Metal–Oxide Interface. J. Am. Chem. Soc. 2017, 139, 5652–5655. [Google Scholar] [CrossRef] [PubMed]
  19. Wan, X.; Zhang, Z.; Yu, W.; Niu, H.; Wang, X.; Guo, Y. Machine-learning-assisted discovery of highly efficient high-entropy alloy catalysts for the oxygen reduction reaction. Patterns 2022, 3, 100553. [Google Scholar] [CrossRef]
  20. Sun, H.; Li, Y.; Gao, L.; Chang, M.; Jin, X.; Li, B.; Xu, Q.; Liu, W.; Zhou, M.; Sun, X. High throughput screening of single atomic catalysts with optimized local structures for the electrochemical oxygen reduction by machine learning. J. Energy Chem. 2023, 81, 349–357. [Google Scholar] [CrossRef]
  21. Chen, Z.; Qi, H.; Wang, H.; Yue, C.; Liu, Y.; Yang, Z.; Pu, M.; Lei, M. The rational design of high-performance graphene-based single-atom electrocatalysts for the ORR using machine learning. Phys. Chem. Chem. Phys. 2023, 25, 18983–18989. [Google Scholar] [CrossRef] [PubMed]
  22. Tiwari, J.N.; Sultan, S.; Myung, C.W.; Yoon, T.; Li, N.; Ha, M.; Harzandi, A.M.; Park, H.J.; Kim, D.Y.; Chandrasekaran, S.S.; et al. Multicomponent electrocatalyst with ultralow Pt loading and high hydrogen evolution activity. Nat. Energy 2018, 3, 773–782. [Google Scholar] [CrossRef]
  23. Gu, Y.; Wei, B.; Legut, D.; Fu, Z.; Du, S.; Zhang, H.; Francisco, J.S.; Zhang, R. Single atom-modified hybrid transition metal carbides as efficient hydrogen evolution reaction catalysts. Adv. Funct. Mater. 2021, 31, 2104285. [Google Scholar] [CrossRef]
  24. Abdelghafar, F.; Xu, X.M.; Jiang, S.P.; Shao, Z.P. Designing single-atom catalysts toward improved alkaline hydrogen evolution reaction. Mater. Rep. Energy 2022, 2, 100144. [Google Scholar] [CrossRef]
  25. Xu, X.M.; Zhong, Y.J.; Wajrak, M.; Bhatelia, T.; Jiang, S.P.; Shao, Z.P. Grain boundary engineering: An emerging pathway toward efficient electrocatalysis. InfoMat 2024, 6, e12608. [Google Scholar] [CrossRef]
  26. Niu, H.; Wan, X.; Wang, X.; Shao, C.; Robertson, J.; Zhang, Z.; Guo, Y. Single-atom rhodium on defective g-C3N4: A promising bifunctional oxygen electrocatalyst. ACS Sustain. Chem. Eng. 2021, 9, 3590–3599. [Google Scholar] [CrossRef]
  27. Zhao, X.; Pei, Y. Single metal atom supported on N-doped 2D nitride black phosphorus: An efficient electrocatalyst for the oxygen evolution and oxygen reduction reactions. J. Phys. Chem. C 2021, 125, 12541–12550. [Google Scholar] [CrossRef]
  28. Chen, J.W.; Wu, S.Y.; Chen, H.T. Unraveling electrochemical oxygen reduction mechanism on single-atom catalysts by a computational investigation. Int. J. Energy Res. 2022, 46, 1032–1042. [Google Scholar] [CrossRef]
  29. Feng, J.X.; Ye, S.H.; Xu, H.; Tong, Y.X.; Li, G.R. Design and Synthesis of FeOOH/CeO2 Heterolayered Nanotube Electrocatalysts for the Oxygen Evolution Reaction. Adv. Mater. 2016, 28, 4698–4703. [Google Scholar] [CrossRef]
  30. Ma, Z.; Cui, Z.; Xiao, C.; Dai, W.; Lv, Y.; Li, Q.; Sa, R. Theoretical screening of efficient single-atom catalysts for nitrogen fixation based on a defective BN nanosheets. Nanoscale 2020, 12, 1541–1550. [Google Scholar] [CrossRef]
  31. Zhao, J.; Chen, Z. Single Mo atom supported on defective boron nitride nanosheets as an efficient electrocatalyst for nitrogen fixation: A computational study. J. Am. Chem. Soc. 2017, 139, 12480–12487. [Google Scholar] [CrossRef]
  32. Agarwal, S.; Kumar, R.; Arya, R.; Singh, A.K. Rational Design of Single-Atom Catalysts for Enhanced Electrocatalytic Nitrogen Reduction Reaction. J. Phys. Chem. C 2021, 125, 12585–12593. [Google Scholar] [CrossRef]
  33. Song, W.; Xie, K.; Wang, J.; Guo, L.; He, C.; Fu, L. Density functional theory study of transition metal single-atoms anchored on graphyne as efficient electrocatalysts for the nitrogen reduction reaction. Phys. Chem. Chem. Phys. 2021, 23, 10418–10428. [Google Scholar] [CrossRef]
  34. Wang, C.; Guo, C. Screening of Transition Metal Single Atom Catalysts Supported on B36 Cluster for Nitrogen Fixation. Int. J. Hydrogen Energy 2022, 47, 5281–5291. [Google Scholar] [CrossRef]
  35. Zeng, H.; Liu, X.; Chen, F.; Chen, Z.; Fan, X.; Lau, W. Single atoms on a nitrogen-doped boron phosphide nanosheets: A new promising bifunctional electrocatalyst for ORR and OER. ACS Appl. Mater. Inter. 2020, 12, 52549–52559. [Google Scholar] [CrossRef] [PubMed]
  36. Wu, J.; Li, J.H.; Yu, Y.X. Single Nb or W atom-embedded BP nanosheets as highly selective and stable electrocatalysts for nitrogen fixation with low-onset potentials. ACS Appl. Mater. Inter. 2021, 13, 10026–10036. [Google Scholar] [CrossRef] [PubMed]
  37. Stan, G.; Ciobanu, C.V.; Thayer, T.P.; Wang, G.T.; Creighton, J.R.; Purushotham, K.P.; Bendersky, L.A.; Cook, R.F. Elastic moduli of faceted aluminum nitride nanotubes measured by contact resonance atomic force microscopy. Nanotechnology 2009, 20, 035706–035711. [Google Scholar] [CrossRef]
  38. Zhang, K.; Pan, M.; Liu, Z.X.; Wang, J.M.; Wang, Y.J.; Deng, H.Q. Theoretically evaluating transition metal activated two-dimensional bilayer tetragonal AlN nanosheet for high-performance HER/OER/ORR electrocatalysts. Comp. Mater. Sci. 2024, 232, 112634. [Google Scholar] [CrossRef]
  39. Wang, J.M.; Wu, H.; Pan, M.; Liu, Z.X.; Han, L.; Huang, Z.; Deng, H.Q. Bilayer tetragonal AlN nanosheets as potential cathodes for Li-O2 batteries. Phys. Chem. Chem. Phys. 2023, 25, 15030–15039. [Google Scholar] [CrossRef]
  40. Zhang, Y.F.; Wang, T.Y.; Wang, F.; Zheng, H.L.; Zeng, Z.Y.; Li, H. Identifying hexagonal 2D planar electrocatalysts with strong OCHO* binding for selective CO2 reduction. J. Mater. Chem. A 2023, 11, 20528–20538. [Google Scholar] [CrossRef]
  41. Kresse, G.; Furthmüller, J. Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys. Rev. B 1996, 54, 11169–11186. [Google Scholar] [CrossRef]
  42. Kresse, G.; Joubert, D. From ultrasoft pseudopotentials to the projector augmented-wave method. Phys. Rev. B 1999, 59, 1758–1775. [Google Scholar] [CrossRef]
  43. Blöchl, P.E. Projector augmented-wave method. Phys. Rev. B Condens 1994, 50, 17953–17979. [Google Scholar] [CrossRef]
  44. Kresse, G.; Furthmüller, J. Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set. Comput. Mater. Sci. 1996, 6, 15–50. [Google Scholar] [CrossRef]
  45. Grimme, S. Semiempirical GGA-type density functional constructed with a longrange dispersion correction. J. Comput. Chem. 2006, 27, 1787–1799. [Google Scholar] [CrossRef]
  46. Nørskov, J.K.; Bligaard, T.; Logadottir, A.; Kitchin, J.; Chen, J.G.; Pandelov, S.; Stimming, U. Trends in the exchange current for hydrogen evolution. J. Electrochem. Soc. 2005, 152, J23–J26. [Google Scholar] [CrossRef]
  47. Wang, V.; Xu, N.; Liu, J.C.; Tang, G.; Geng, W.T. VASPKIT: A user-friendly interface facilitating high-throughput computing and analysis using VASP code. Comput. Phys. Commun. 2021, 267, 108033. [Google Scholar] [CrossRef]
  48. Montoya, J.H.; Tsai, C.; Vojvodic, A.; Nørskov, J.K. The Challenge of Electrochemical Ammonia Synthesis: A New Perspective on the Role of Nitrogen Scaling Relations. ChemSusChem 2015, 8, 2180–2186. [Google Scholar] [CrossRef] [PubMed]
  49. Zhang, L.; Mallikarjun Sharada, S.; Singh, A.R.; Rohr, B.A.; Su, Y.; Qiao, L.; Nørskov, J.K. A theoretical study of the effect of a non-aqueous proton donor on electrochemical ammonia synthesis. Phys. Chem. Chem. Phys. 2018, 20, 4982–4989. [Google Scholar] [CrossRef] [PubMed]
  50. Ying, Y.; Fan, K.; Luo, X.; Qiao, J.; Huang, H. Transition metal-tetracyanoquinodimethane monolayers as single-atom catalysts for the electrocatalytic nitrogen reduction reaction. Mater. Adv. 2020, 1, 1285–1292. [Google Scholar] [CrossRef]
  51. Rittle, J.; Peters, J.C. An Fe-N2 Complex That Generates Hydrazine and Ammonia via Fe=NNH2: Demonstrating a Hybrid Distal-to-Alternating Pathway for N2 Reduction. J. Am. Chem. Soc. 2016, 138, 4243–4248. [Google Scholar] [CrossRef] [PubMed]
  52. Del Castillo, T.J.; Thompson, N.B.; Peters, J.C. A Synthetic Single-Site Fe Nitrogenase: High Turnover, Freeze-Quench 57Fe Mössbauer Data, and a Hydride Resting State. J. Am. Chem. Soc. 2016, 138, 5341–5350. [Google Scholar] [CrossRef] [PubMed]
  53. Abghoui, Y.; Skúlason, E. Onset potentials for different reaction mechanisms of nitrogen activation to ammonia on transition metal nitride electro-catalysts. Catal. Today 2017, 286, 69–77. [Google Scholar] [CrossRef]
  54. Shen, X.P.; Liu, C.; Zhang, Q.F. Single transition atom-doped antimonene as a highly efficient electrocatalyst for the nitrogen reduction reaction: A DFT study. Mater. Adv. 2024, 5, 730–740. [Google Scholar] [CrossRef]
  55. Légaré, M.A.; Bélanger-Chabot, G.; Dewhurst Rian, D.; Welz, E.; Krummenacher, I.; Engels, B.; Braunschweig, H. Nitrogen fixation and reduction at boron. Science 2018, 359, 896–900. [Google Scholar] [CrossRef]
  56. Vurgaftman, I.; Meyer, J.R. Band parameters for nitrogen-containing semiconductors. J. Appl. Phys. 2003, 94, 3675–3696. [Google Scholar] [CrossRef]
Molecules 29 05768 g001
Figure 1. (a) The geometric structures of TM atoms anchored on the AlN monolayer with Al monovacancy. The anchoring sites are encircled in red colors. The binding energies of (b) 3d, (c) 4d, and (d) 5d TM atoms doped the AlN monolayer, respectively.
Figure 1. (a) The geometric structures of TM atoms anchored on the AlN monolayer with Al monovacancy. The anchoring sites are encircled in red colors. The binding energies of (b) 3d, (c) 4d, and (d) 5d TM atoms doped the AlN monolayer, respectively.
Molecules 29 05768 g001
Molecules 29 05768 g002
Figure 2. Screening results of TM@AlN for the NRR based on the free energy changes in the first hydrogenation step (△G(*N2–*NNH) with end-on or side-on configurations and last hydrogenation steps (△G(*NH2–*NH3)), respectively.
Figure 2. Screening results of TM@AlN for the NRR based on the free energy changes in the first hydrogenation step (△G(*N2–*NNH) with end-on or side-on configurations and last hydrogenation steps (△G(*NH2–*NH3)), respectively.
Molecules 29 05768 g002
Molecules 29 05768 g003
Figure 3. The optimized geometry structures of key intermediates for NRR on the Os@AlN with N2 end-on adsorption configuration.
Figure 3. The optimized geometry structures of key intermediates for NRR on the Os@AlN with N2 end-on adsorption configuration.
Molecules 29 05768 g003
Molecules 29 05768 g004
Figure 4. The optimized geometry structures of key intermediates for NRR on the Os@AlN with N2 side-on adsorption configuration.
Figure 4. The optimized geometry structures of key intermediates for NRR on the Os@AlN with N2 side-on adsorption configuration.
Molecules 29 05768 g004
Molecules 29 05768 g005
Figure 5. Gibbs free energy diagrams of NRR processes at zero (blue lines) and applied potential (red lines) via the (a) distal, (b) alternating, (c) consecutive, and (d) enzymatic pathways on Os@AlN, respectively. * represents the origin Os@AlN.
Figure 5. Gibbs free energy diagrams of NRR processes at zero (blue lines) and applied potential (red lines) via the (a) distal, (b) alternating, (c) consecutive, and (d) enzymatic pathways on Os@AlN, respectively. * represents the origin Os@AlN.
Molecules 29 05768 g005
Molecules 29 05768 g006
Figure 6. The partial density of states (PDOS) of (a) gaseous N2-s and N2-p, (b) defective AlN Al-s, Al-p, N-s and N-p, (c) Al-s, Al-p, N-s, N-p and Os-d of Os@AlN, and (d) N2 adsorbed on Os@AlN with end-on configuration. The Fermi level is set to zero and denoted by a black dashed line.
Figure 6. The partial density of states (PDOS) of (a) gaseous N2-s and N2-p, (b) defective AlN Al-s, Al-p, N-s and N-p, (c) Al-s, Al-p, N-s, N-p and Os-d of Os@AlN, and (d) N2 adsorbed on Os@AlN with end-on configuration. The Fermi level is set to zero and denoted by a black dashed line.
Molecules 29 05768 g006
Molecules 29 05768 g007
Figure 7. The electron localization function (ELF) maps of Os@AlN (a) and N2 adsorbed on Os@AlN with end-on configuration (b).
Figure 7. The electron localization function (ELF) maps of Os@AlN (a) and N2 adsorbed on Os@AlN with end-on configuration (b).
Molecules 29 05768 g007
Molecules 29 05768 g008
Figure 8. (a) Bader charges for three Os@AlN moieties along the distal pathway. (b) Charge density difference for N2 adsorbed on Os@AlN with end-on configuration, where the isosurface value is set to be 0.008 e Å−3, and the positive and negative charges are shown in yellow and cyan, respectively.
Figure 8. (a) Bader charges for three Os@AlN moieties along the distal pathway. (b) Charge density difference for N2 adsorbed on Os@AlN with end-on configuration, where the isosurface value is set to be 0.008 e Å−3, and the positive and negative charges are shown in yellow and cyan, respectively.
Molecules 29 05768 g008
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Shen, X.; Zhang, Q. Rational Design of Novel Single-Atom Catalysts of Transition-Metal-Doped 2D AlN Monolayer as Highly Effective Electrocatalysts for Nitrogen Reduction Reaction. Molecules 2024, 29, 5768. https://doi.org/10.3390/molecules29235768

AMA Style

Shen X, Zhang Q. Rational Design of Novel Single-Atom Catalysts of Transition-Metal-Doped 2D AlN Monolayer as Highly Effective Electrocatalysts for Nitrogen Reduction Reaction. Molecules. 2024; 29(23):5768. https://doi.org/10.3390/molecules29235768

Chicago/Turabian Style

Shen, Xiaopeng, and Qinfang Zhang. 2024. "Rational Design of Novel Single-Atom Catalysts of Transition-Metal-Doped 2D AlN Monolayer as Highly Effective Electrocatalysts for Nitrogen Reduction Reaction" Molecules 29, no. 23: 5768. https://doi.org/10.3390/molecules29235768

APA Style

Shen, X., & Zhang, Q. (2024). Rational Design of Novel Single-Atom Catalysts of Transition-Metal-Doped 2D AlN Monolayer as Highly Effective Electrocatalysts for Nitrogen Reduction Reaction. Molecules, 29(23), 5768. https://doi.org/10.3390/molecules29235768

Article Metrics

Back to TopTop