Nickel-modified In2O3 with inherent oxygen vacancies for CO2 hydrogenation to methanol

This study is led by Prof. Peng Gao and Prof. Shenggang Li (CAS Key Laboratory of Low-Carbon Conversion Science and Engineering, Shanghai Advanced Research Institute).

In this paper, the hydrogenation metals (Co, Ni and Cu) promoted In₂O₃ catalysts with a similar loading of 1 wt.% were prepared by the hydrothermal method. It was found that the Ni-promoted In₂O₃ catalyst with high dispersion possesses the largest amount of oxygen vacancies and the strongest ability for H₂ activation, and exhibited the highest CO₂ conversion and STY of CH₃OH, which reached 0.390 g_MeOH g_cat⁻¹ h⁻¹ with CH₃OH selectivity of 68.7%. In addition, the Ni-promoted In₂O₃ catalyst exhibits very stable performance over 120 h on stream, which suggests the promising prospect for industrial applications. Moreover, a series of Ni modified In₂O₃ catalysts with different surface Ni contents were prepared to further investigate the effect of oxygen vacancy properties on the catalytic behavior of CO₂ hydrogenation to methanol. Surface Ni doping was found to promote the formation of oxygen defects on the In₂O₃ surface, resulting in higher CO₂ reactivity, whereas the Ni-promoted In₂O₃ catalyst with more subsurface Ni showed higher methanol selectivity and productivity. The catalytic performance of our Ni/In₂O₃ catalysts was further rationalized by DFT calculations and microkinetic simulations. DFT-based microkinetic simulations show that CO formation is preferred at the oxygen vacancy site on the surface-doped Ni/In₂O₃ catalyst, whereas CH₃OH formation is favored at that on the subsurface-doped Ni/In₂O₃ catalyst especially at relatively low reaction temperatures. This work thus provides theoretical guidance for improving the CO₂ reactivity of In₂O₃-based catalysts while maintaining high methanol selectivity.

This study not only provides a better understanding of the effect of transition-metal promoters with high dispersion on the catalytic performance, but also suggests that DFT-based microkinetic simulations can provide reliable prediction on the catalytic activity and product selectivity for the CO₂ hydrogenation to methanol reaction over industrially relevant metal-promoted oxide catalysts, which is crucial for their computer-aided rational design.

See the article:

Nickel-modified In₂O₃ with inherent oxygen vacancies for CO₂ hydrogenation to methanol

http://engine.scichina.com/doi/10.1007/s11426-023-1929-1