Effect of Cs and Ba promoters on Ni/graphite catalysts for CO2 conversion via the reverse water gas shift reaction†

Obtaining syngas from CO₂ and green hydrogen via the reverse water gas shift (RWGS) reaction is a promising strategy for mitigating the greenhouse effect. Additionally, CO obtained as the product holds significant potential in the syngas-based chemical industry. In this context, we developed efficient Ni-based catalysts for the RWGS reaction at a low temperature. In our approach, we selected Cs and Ba as catalytic promoters and utilized high-surface-area graphite (HSAG400) as a support to maximize the interaction between the metal and promoter. Our study revealed that both promoters helped in enhancing the CO₂ conversion but had opposite effects in the RWGS reaction. In particular, the use of the Cs promoter boosted the CO selectivity up to 95%, while the addition of Ba proved to be detrimental to CO selectivity.