Regulation products selectivity on PtCo alloy catalyst in CO2 hydrogenation through enhanced CO competitive adsorption and C–C coupling

The hydrogenation of CO 2 into high-value-added chemicals represents one of the most effective strategies for mitigating the greenhouse effect and addressing the energy crisis. In this study, the incorporation of Pt into Co-based catalysts is utilized to modulate the CO competitive adsorption capacity and reaction pathways, thereby significantly enhances the C–C coupling and the selectivity of C 2+ hydrocarbons during CO 2 hydrogenation. The formation of PtCo alloy in the catalysts is confirmed by X-ray absorption spectroscopy, in-situ X-ray diffraction, X-ray photoelectron spectroscopy and scanning transmission electron microscopy analyses. The study reveals that the presence of PtCo alloy alters the competitive adsorption behavior of CO and CO 2 on the catalyst, and enables CO to replace CO 2 as the strongly adsorbed species on the catalyst. Density functional theory calculations demonstrate that the PtCo alloy exhibits enhanced CO adsorption energy and reduced formation energy barrier for formate compared with pure Co. This is responsible for the emergence of an additional formate pathway on the PtCo catalyst. Consequently, the 2%PtCo catalyst achieves a C 2+ selectivity of 18.5% under conditions of 350 °C and 3 MPa, markedly higher than the 1.9% over the pure Co catalyst. PtCo catalysts possesses 83.6 mmol·g –1 ·h –1 C 2+ yield, outperforming the Fe-based reference catalyst by a factor of 4. The study presents a novel catalyst design concept for increasing C 2+ selectivity through regulating the competitive adsorption between intermediate and reactant.