Nickel-modified indium with inherent oxygen vacancies for carbon dioxide hydrogenation to methanol

In a study led by Prof. Peng Gao and Prof. Shenggang Li (CAS Key Laboratory of Low-Carbon Conversion Science and Engineering, Shanghai Advanced Research Institute), it was found that 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 a 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.

The findings are published in the journal Science China Chemistry.

More information:
Zixuan Zhou et al, Nickel-modified In₂O₃ with inherent oxygen vacancies for CO2 hydrogenation to methanol, Science China Chemistry (2024). DOI: 10.1007/s11426-023-1929-1

Provided by Science China Press