Catalysts

22 pages, 1099 KB

Open AccessReview

Synergistic Conversion and Catalytic Upgrading of Seaweed Biomass for Sustainable Bioenergy: Advances, Challenges, and Future Prospects

by Qing Xu, Shenwei Zhang and Shengxian Xian

Catalysts 2025, 15(11), 1008; https://doi.org/10.3390/catal15111008 (registering DOI) - 24 Oct 2025

Abstract

Seaweed holds significant promise as a renewable feedstock for bioenergy due to its rapid growth, carbon sequestration capacity, and non-competition with terrestrial agriculture. This review examines recent progress in multi-method synergies for optimized energy conversion from seaweed biomass. Physical pre-treatments (e.g., drying, milling, [...] Read more.

Seaweed holds significant promise as a renewable feedstock for bioenergy due to its rapid growth, carbon sequestration capacity, and non-competition with terrestrial agriculture. This review examines recent progress in multi-method synergies for optimized energy conversion from seaweed biomass. Physical pre-treatments (e.g., drying, milling, ultrasound, microwave) enhance substrate accessibility but face energy intensity constraints. Chemical processes (acid/alkali, solvent extraction, catalysis) improve lipid/sugar recovery and bio-oil yields, especially via hydrodeoxygenation (HDO) and catalytic cracking over tailored catalysts (e.g., ZSM-5), though cost and byproduct management remain challenges. Biological methods (enzymatic hydrolysis, fermentation) enable eco-friendly valorization but suffer from scalability and enzymatic cost limitations. Critically, integrated approaches—such as microwave-solvent systems or hybrid thermochemical-biological cascades—demonstrate superior efficiency over singular techniques. Upgrading pathways for liquid bio-oil (e.g., HDO, catalytic pyrolysis) show considerable potential for drop-in fuel production, while solid-phase biochar and biogas offer carbon sequestration and circular economy benefits. Future priorities include developing low-cost catalysts, optimizing process economics, and scaling synergies like hydrothermal liquefaction coupled with catalytic upgrading to advance sustainable seaweed biorefineries. Full article

(This article belongs to the Topic Advanced Bioenergy and Biofuel Technologies)

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18 pages, 1211 KB

Open AccessFeature PaperReview

Applications and Perspectives of Life Cycle Assessment in the Green Design of Single-Atom Catalysts

by He Gao, Ruonan Guo, Changsheng Guo, Ningqing Lv and Jian Xu

Catalysts 2025, 15(11), 1007; https://doi.org/10.3390/catal15111007 - 23 Oct 2025

Abstract

Single-atom catalysts (SACs) have attracted extensive attention owing to their outstanding catalytic performance and nearly complete atom utilization efficiency. However, the environmental sustainability of SACs across their full life cycle has not yet been systematically investigated. This review emphasizes the necessity of integrating [...] Read more.

Single-atom catalysts (SACs) have attracted extensive attention owing to their outstanding catalytic performance and nearly complete atom utilization efficiency. However, the environmental sustainability of SACs across their full life cycle has not yet been systematically investigated. This review emphasizes the necessity of integrating life cycle assessment (LCA) into SACs to support their sustainable development. By analyzing the structural characteristics, synthesis strategies, and representative application fields, this study examines how LCA principles can be employed to reveal the hidden environmental burdens associated with raw material extraction, synthesis processes, usage stages, and end-of-life management. Based on existing LCA case studies of catalytic materials, this review identifies the key challenges in the SACs field and proposes a preliminary framework for sustainable SAC design with LCA as a guiding approach. Finally, the review summarizes the current challenges and future perspectives, emphasizing that developing more specific evaluation standards, improving database construction, and adopting dynamic assessment methods are essential to shift LCA from a passive evaluation tool to an active design strategy that drives the green development of next-generation SACs. Full article

(This article belongs to the Special Issue Single-Atom Catalysts: Current Trends, Challenges, and Prospects)

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35 pages, 3095 KB

Open AccessFeature PaperReview

Biomass Conversion to Value-Added Chemicals and Fuels Using Natural Minerals as Catalysts or Catalytic Supports

by Sotiris Lycourghiotis and Eleana Kordouli

Catalysts 2025, 15(11), 1006; https://doi.org/10.3390/catal15111006 - 23 Oct 2025

Abstract

Biofuels and value-added chemicals can be produced using biomass. These products can substitute the corresponding petroleum-based ones, reducing the carbon footprint, ensuring domestic production, and minimizing/exploiting organic wastes in a circular economy philosophy. Natural mineral-based catalysts seem to be a promising, eco-friendly, and [...] Read more.

Biofuels and value-added chemicals can be produced using biomass. These products can substitute the corresponding petroleum-based ones, reducing the carbon footprint, ensuring domestic production, and minimizing/exploiting organic wastes in a circular economy philosophy. Natural mineral-based catalysts seem to be a promising, eco-friendly, and low-cost approach for biomass valorization. This article attempts to highlight the potential of natural mineral-based catalysts for various processes targeting the above valorization. Natural zeolites and clays can be used as catalysts/CO₂ adsorbents and catalytic supports in various biorefinery processes (pyrolysis, gasification, hydrothermal liquefaction, esterification/transesterification, hydrotreatment, cracking, isomerization, oxidation, condensation, etc.). Acid/base, redox, and textural properties of these materials are key factors for their catalytic performance and can be easily regulated by suitable treatments, like calcination, acid/base-washing, metal impregnation, doping, etc., which are discussed in this article. The application of natural minerals in biorefinery processes makes them greener, cost-effective, and easily scalable. Full article

(This article belongs to the Special Issue Advanced Catalysts for Biomass Pyrolysis)

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17 pages, 3263 KB

Open AccessArticle

Hydrogenolysis of Biomass-Based Furfuryl Alcohol into 1,2-Pentanediol over Magnesium Oxide-Supported Pt-Y Bimetallic Catalysts

by Kuo Zhou, Jialin Xu, Shengrong Guo and Hongjun Wu

Catalysts 2025, 15(11), 1005; https://doi.org/10.3390/catal15111005 - 22 Oct 2025

Abstract

The catalytic synthesis of 1,2-pentanediol from biomass-derived feedstocks is of remarkable significance for addressing current environmental challenges and energy crises. In this paper, a series of Pt-based catalysts were prepared and evaluated in the hydrogenolysis of furfuryl alcohol. The 5Pt0.5Y/MgO provided a 1,2-pentanediol [...] Read more.

The catalytic synthesis of 1,2-pentanediol from biomass-derived feedstocks is of remarkable significance for addressing current environmental challenges and energy crises. In this paper, a series of Pt-based catalysts were prepared and evaluated in the hydrogenolysis of furfuryl alcohol. The 5Pt0.5Y/MgO provided a 1,2-pentanediol yield of 68.9% and a tetrahydrofurfuryl alcohol yield of 19.8% with 98.1% conversion of furfuryl alcohol, at 200 °C and 2 MPa H₂ for 10 h. The promotional effect of yttrium on the catalytic performance was investigated through catalytic reaction and comprehensive characterization. It was found that the reducibility of Pt species was suppressed by the introduction of Y species, resulting in reduced activity compared to the 5Pt/MgO catalyst. However, the addition of Y notably shifted the reaction pathway towards 1,2-pentanediol formation at the expense of tetrahydrofurfuryl alcohol selectivity. This increase in 1,2-pentanediol selectivity was attributed to a higher concentration of medium-strength basic sites on the Y-modified Pt catalyst. Furthermore, the strong interaction between Y₂O₃, Pt particles, and the MgO support led to high Pt dispersion and stability on the MgO surface, consequently yielding satisfactory recyclability. Full article

(This article belongs to the Special Issue Advanced Catalysts Design and Catalytic Conversion of Biomass to High-Value Products)

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15 pages, 1555 KB

Open AccessArticle

Selective Ammoxidation of Methanol to Hydrogen Cyanide over Silica-Supported FeMo Oxide Catalysts: Experiments and Kinetic Modeling

by Bo Wang and Yuhuan Zhao

Catalysts 2025, 15(11), 1004; https://doi.org/10.3390/catal15111004 - 22 Oct 2025

Abstract

We investigated the ammoxidation of methanol for the production of hydrogen cyanide. Silica-supported FeMo oxide catalysts achieved above 98% conversion of methanol, with more than 90% selectivity for the ammoxidation reaction product, HCN. The oxidation products, CO and CO₂, were formed [...] Read more.

We investigated the ammoxidation of methanol for the production of hydrogen cyanide. Silica-supported FeMo oxide catalysts achieved above 98% conversion of methanol, with more than 90% selectivity for the ammoxidation reaction product, HCN. The oxidation products, CO and CO₂, were formed with a molar selectivity less than 10%, depending on the operating conditions. The kinetics of the ammoxidation of methanol were investigated in a fixed-bed tubular reactor at 320–445 °C and atmospheric pressure. A Mars–van Krevelen model accounted for the ammoxidation of methanol as well as the formation of CO and CO₂. The Levenberg–Marquardt algorithm was used to estimate the model parameters, which were statistically significant and fit the experimental data well. The model can be used to simulate and guide the operation of the industrial reactor. Full article

(This article belongs to the Section Catalytic Materials)

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19 pages, 2899 KB

Open AccessArticle

A Novel Choline Alkali–Thiourea Pretreatment for Enhanced Enzymatic Hydrolysis of Reed Straw

by Lei Gong, Jinchun Liu, Menghao Li, Jiaying Chang, Liuchang Sun and Jie Zhu

Catalysts 2025, 15(11), 1003; https://doi.org/10.3390/catal15111003 - 22 Oct 2025

Abstract

A new alkaline deep eutectic solvent (ChOH-TH) was developed using choline hydroxide and thiourea to pretreat reed straw for enhanced enzymatic hydrolysis. The study systematically examined the impact of ChOH-TH pretreatment on reed straw’s composition, microstructure, crystalline structure, and enzymatic saccharification efficiency to [...] Read more.

A new alkaline deep eutectic solvent (ChOH-TH) was developed using choline hydroxide and thiourea to pretreat reed straw for enhanced enzymatic hydrolysis. The study systematically examined the impact of ChOH-TH pretreatment on reed straw’s composition, microstructure, crystalline structure, and enzymatic saccharification efficiency to determine optimal conditions. Results showed that adding 70% deionized water to ChOH-TH and pretreating at 70 °C for 3 h effectively removed 70.73% of lignin from reed straw. This condition led to a 93.52% increase in reducing sugar output from the pretreated cellulose-enriched substrate, a 12.04-fold rise compared to untreated straw. Structural analysis revealed enhanced cellulose crystallinity to 51.38% in the residual biomass, along with surface modifications and changes in functional groups and components, contributing to improved enzymatic hydrolysis efficiency. Moreover, ChOH-TH maintained a 60.41% reducing sugar yield after five reuse cycles in the enzymatic hydrolysis of pretreated reed straw, highlighting its reusability and sustainability. It showed effective pretreatment performance on various lignocellulosic biomass types, indicating universality. The optimized ChOH-TH solvent is efficient, stable, and versatile for biomass pretreatment, improving enzymatic hydrolysis efficiency with economic and environmental benefits. This presents a green pathway for utilizing lignocellulosic waste with significant academic and industrial potential. Full article

(This article belongs to the Special Issue Advances in Catalytic Conversion of Lignocellulose Refining)

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12 pages, 3916 KB

Open AccessArticle

Pore Structure Modification of the Mixed Metal Oxides Derived from Co-Al Layered Double Hydroxides and Catalytic Performance Enhancement for Aerobic Oxidation of Benzyl Alcohol

by Qian Zhang, Xia Tan, Yinjie Hu, Haonan Cui, Xiao Lin, Fei Li, Huibin Lei and Ou Zhuo

Catalysts 2025, 15(11), 1002; https://doi.org/10.3390/catal15111002 - 22 Oct 2025

Abstract

The mixed metal oxides (MMOs) derived from layered double hydroxides (LDHs) are a typical class of porous materials and have attracted significant attention across various fields due to their high surface area, rich porous structures and various compositions. Regulating the pore structure of [...] Read more.

The mixed metal oxides (MMOs) derived from layered double hydroxides (LDHs) are a typical class of porous materials and have attracted significant attention across various fields due to their high surface area, rich porous structures and various compositions. Regulating the pore structure of MMOs remains an urgent need because of the growing demand for numerous applications including adsorption, catalysis, and energy conversion. Controlling the lateral size of the lamellar crystals in the Co–Al LDH precursor allowed us to engineer the pore structure of Co–Al MMO, an architecture formed by the stacking of these lamellar flakes. The pore size distribution of the Co–Al MMO has been adjusted in the range from several nanometer to hundreds of nanometers. The sample with the optimized pore sizes exhibited a much higher catalytic reaction rate in the aerobic oxidation reaction of benzyl alcohol, about 4.2 times that of the control sample. Further research demonstrated that the high activity was favored by the improved mass transfer rate in the optimized pore architecture. Moreover, sodium silicate was employed as a cross-linking agent to enhance the cohesion within the secondary particles, which consist of stacked lamellar flakes. The resulting silicate-modified Co–Al MMO demonstrated significantly improved catalytic durability, maintaining stable performance over five consecutive reuse cycles—the performance that substantially exceeded that of its un-modified counterpart. Full article

(This article belongs to the Topic Advanced Materials in Chemical Engineering)

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Catalysts, Volume 15, Issue 11 (November 2025) – 7 articles

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