**1. Introduction**

Global warming is an imminent threat to our planet. It is essential to diminish the emission of greenhouse gases, especially carbon dioxide (CO2), to slow global warming. Different sources of CO2 emissions are a significant part to dictate by the ignition of liquid, solid, and gaseous chemicals. Rising atmospheric CO2 concentrations and the increasing temperature of the planet's surface have increased public awareness of this problem [1]. CO2 is utilized in the in the manufacturing industries, which is mostly released by the combustion of fossil fuels [2]. Among different products, methanol and formic acid can be synthesized from CO2 which is used directly as fuels or to generate H2 on demand at low temperatures (<100 ◦C) [1]. However, CO2 can be used efficiently in various value-adding strategies and research pursuits which are converted waste emissions into valuable chemicals products, such as hydrocarbons and oxygenates [3]. Electrochemical activation technologies and conversion of CO2 and H2O into hydrocarbons has seen a marked increase in research activity over the past few years [4]. The impressive separation and utilization of CO2 technologies in a higher challenge of organizing than other gases [5]. The development of CO2 for novel approaches can add value to CO2 recycling as it may result in commercially useful carbon-based products. Today, CO2 is used commercially in the production of pharmaceuticals, air-conditioning systems, beverages, fertilizers, inert agents for food packaging, the water treatment process, fire extinguishers, and other applications. To achieve sustainable economic growth, it is crucial to study the conversion of CO2 into carbon-based chemicals and materials. Industrial companies use massive amounts of CO2 to enhance oil restoration. Biomass conversion to fuels also utilizes CO2 [6]. Recently, Drisdell et al. [7] reported that oxide-derived copper catalysts are better at making fuel products from CO2. According to Drisdell group, CO2 is initially converted into carbon monoxide under first conditions for producing fuel and then hydrocarbon chains are developed. Oxide-derived catalysts are better, not because they have oxygen remaining while they

reduce carbon monoxide, but because the process of removing the oxygen creates a metallic copper structure that is better at forming ethylene. Using solar energy to convert CO2 into most needed fuels has the potential to decrease global warming impact (GWI) and produce sustainable fuels at large scale [8]. A great deal of research has focused on combining heteroatoms in the carbon structure to improve the exchangeable action of CO2 along with the adsorbent surfaces over the past few years [6].

CO2 utilization has recently become an alluring sector of research, as it will help to alleviate climate change and reduce industrial operating costs. Globally, CO2 capture and utilization are significant goals for chemicals and materials scientists [9]. Researchers are working to diminish the negative effects of CO2 by adsorption [10,11], reduction, and fixation as well as through the development of metal-organic frameworks (MOFs), zeolites, polymers and micro-porous carbons [12]. Currently, CO2 is used in an impenetrable phase under harsh conditions as an active promoter, making it a green substitute for organic compounds [13]. There are several limitations of dense phase CO2 media, including the high pressures required to assure sufficient solubility of various transition metal catalysts and low reaction rates [14]. Jessop et al. proposed, as a solution to the solubility issue, an exchangeable process using 1,8-diazabicyclo-[5.4.0]-undec-7-ene. Additionally, they were able to eliminate partition steps by adjusting polarities with the use of CO2 [15]. Another way to utilize CO2 is to use it as an oxygen source. Park et al. demonstrated the mild oxidant character of CO2 in the oxidative dehydrogenation of various types of alkyl benzene in both liquid and gaseous phases [16,17]. Using CO2 in catalytic reactions offers other advantages; for instance, absorption of hydrogen from alkanes, alkyl aromatics, and alcohols using CO2 as a reactant to create CO and oxygen species results in an expedited reaction rate, increased conversion, higher yield, and suppression of oxidation [16]. The presence of both CO2 and O2 increases the reaction rates as well as the conversion and selectivity. This process is performed under subcritical pressures of CO2 and involves CO2-promoted systems (CPS) instead of a CO2-expanded system, as evidenced by the low-pressure approach as well as catalytic CO2 activation. Recently developed CO2 use technologies require the utilization of high-energy initiators [18]. Although great progress has been made in the carbon dioxide sector, there remain innate limitations, such as high-energy requirements, and the hydrogen recession. CO2 has various benefits as a mild oxidant over several oxidizing promoters tested for oxidative dehydrogenation reaction, such as dry air, SO2, and N2O [19]. C1 products such as methanol, formic acid has become possible to produce with high initial selectivity by using CO2 over simple metal-based catalysts [4]. CO2 promotes selectivity by contaminating the non-selective species of several catalysts, preventing the production of several by-products [20]. Additionally, CO2 is used as a carbon source in the decoking process (C + CO2 = 2CO) which sustains catalytic activity [21]. Therefore, the oxidative dehydrogenation (ODH) reaction with CO2 primarily considered to be a gas-interposed adaptation of the catalyst surface. This affects the diffusion, adsorption, and red-ox characteristics of the catalyst [22]. In recent years, the CO2 conversion process has been utilized in various sectors, including thermo-chemical [23], photochemical [24], solar-chemical [25], electrochemical [26], biochemical [27] and homogenous catalysis [28] (Scheme 1).

In this review, we discuss a way to improve various technologies using CO2 as a mild oxidant and enhancer for the production of essential chemicals. The purpose of this review is to illustrate the limitations and scope of CO2 utilization and to highlight the advantages and challenges of carbon management. The use of CO2 as a feedstock is a major goal, which could have a modest impact in practice, but may impart a significant symbolic effect on worldwide carbon stability. The further impact would result from the use of CO2 as a soft oxidant and for oxidative dehydrogenation in catalytic reactions. Bartholomew et al. [29] studied the oxidizing capability of different gases in the gasification of coke. Their activities were ranked as follows: O2 (105) > H2O (3) > CO2 (1) > H2 (0.003). This demonstrates that carbon dioxide is less active than molecular oxygen and water, but still offers high oxidative capacity. However, carbon dioxide has the greatest heat capability among the commonly used alternative gases. Furthermore, CO2 can reduce the occurrence of hotspots, which cause problems, such as catalyst deactivation, runaway temperature, and undesirable product oxidation.

**Scheme 1.** The various chemical processes for CO2 conversion.
