Yolk-Shell structured NiCo@SiO2 nanoreactor for CO2 upgrading via reverse water-gas shift reaction

Anti-Sintering Ni-W Catalytic Layer on Reductive Tungsten Carbides for Superior High-Temperature CO2 Reduction

The reverse water-gas shift (RWGS) reaction stands out as a promising approach for selectively converting CO2 into CO, which can then be upgraded into high-value-added products. While designing high selectivity and stability catalysts for RWGS reaction remains a significant challenge. In this study, an efficient and ultra-stable Ni-W catalytic layer on reductive WC (NiAWC) is designed as an anti-sintering catalyst for superior high-temperature RWGS reaction. Benefiting from the unique structures, the NiAWC catalyst exhibits exceptionally high performances with a CO production rate of 1.84 molCO gNi -1 h-1 and over 95% CO selectivity, maintaining stability for 120 h at 500 °C. Even after 300 h of continuous testing at 600 °C and five aging cycles at 800 °C, the activity loss is only 0.34% and 0.83%, respectively. Unlike the conventional mechanism in RWGS reaction, it is demonstrated that the Ni-W limited coordination can stabilize the Ni sites and allow a pre-oxidation of Niδ+ by CO, which produces an O* electronic reservoir and hinders the charge transfer from Ni to W-O, thereby avoiding the dissolution of Ni atoms. The design of new, efficient, and selective catalysts through metal-substrate synergistic effects is suggested to offer a promising path to engineering superior thermal catalysts.

Recent Advances in Hydrogenation of CO2 to CO with Heterogeneous Catalysts Through the RWGS Reaction

With the continuous increase in CO2 emissions, primarily from the combustion of coal and oil, the ecosystem faces a significant threat. Therefore, as an effective method to minimize the issue, the Reverse Water Gas Shift (RWGS) reaction which converts CO2 towards CO attracts much attention, is an environmentally-friendly method to mitigate climate change and lessen dependence on fossil fuels. Nevertheless, the inherent thermodynamic stability and kinetic inertness of CO2 is a big challenge under mild conditions. In addition, it remains another fundamental challenge in RWGS reaction owing to CO selectivity issue caused by CO2 further hydrogenation towards CH4 . Up till now, a series of catalysis systems have been developed for CO2 reduction reaction to produce CO. Herein, the research progress of the well-performed heterogeneous catalysts for the RWGS reaction were summarized, including the catalyst design, catalytic performance and reaction mechanism. This review will provide insights into efficient utilization of CO2 and promote the development of RWGS reaction.

Recent Application of Core-Shell Nanostructured Catalysts for CO2 Thermocatalytic Conversion Processes

Carbon-intensive industries must deem carbon capture, utilization, and storage initiatives to mitigate rising CO2 concentration by 2050. A 45% national reduction in CO2 emissions has been projected by government to realize net zero carbon in 2030. CO2 utilization is the prominent solution to curb not only CO2 but other greenhouse gases, such as methane, on a large scale. For decades, thermocatalytic CO2 conversions into clean fuels and specialty chemicals through catalytic CO2 hydrogenation and CO2 reforming using green hydrogen and pure methane sources have been under scrutiny. However, these processes are still immature for industrial applications because of their thermodynamic and kinetic limitations caused by rapid catalyst deactivation due to fouling, sintering, and poisoning under harsh conditions. Therefore, a key research focus on thermocatalytic CO2 conversion is to develop high-performance and selective catalysts even at low temperatures while suppressing side reactions. Conventional catalysts suffer from a lack of precise structural control, which is detrimental toward selectivity, activity, and stability. Core-shell is a recently emerged nanomaterial that offers confinement effect to preserve multiple functionalities from sintering in CO2 conversions. Substantial progress has been achieved to implement core-shell in direct or indirect thermocatalytic CO2 reactions, such as methanation, methanol synthesis, Fischer-Tropsch synthesis, and dry reforming methane. However, cost-effective and simple synthesis methods and feasible mechanisms on core-shell catalysts remain to be developed. This review provides insights into recent works on core-shell catalysts for thermocatalytic CO2 conversion into syngas and fuels.

CO2 Conversion via Reverse Water Gas Shift Reaction Using Fully Selective Mo–P Multicomponent Catalysts

The reverse water gas shift reaction (RWGS) has attracted much attention as a potential means to widespread utilization of CO₂ through the production of synthesis gas. However, for commercial implementation of RWGS at the scales needed to replace fossil feedstocks with CO₂, new catalysts must be developed using earth abundant materials, and these catalysts must suppress the competing methanation reaction completely while maintaining stable performance at elevated temperatures and high conversions producing large quantities of water. Herein we identify molybdenum phosphide (MoP) as a nonprecious metal catalyst that satisfies these requirements. Supported MoP catalysts completely suppress methanation while undergoing minimal deactivation, opening up possibilities for their use in CO₂ utilization.