Ni/Al₂O₃ is an active catalysts for CO₂ hydrogenation to both CH₄ and CO. By doping with Ga, we succeeded in shifting the selectivity of these catalysts almost completely toward CO. In-situ IR spectroscopy studies showed that the catalyst activity is directly related to the concentration of surface hydroxyl groups that are responsible for the adsorption of CO₂ and the formation of intermediate bicarbonates and formates on the catalyst surface. The addition of Ga improved the Ni dispersion which was concomitant with the formation of a Ni-Ga layer on the surface of alumina, thereby reducing the surface hydroxyl concentration. The reduced and weakened interaction between the intermediate products, i.e. bicarbonates and formates, and the catalyst surface, increased the CO selectivity from ∼40 % to 98 %.

Ni/Al ₂ O ₃是 CO ₂加氢生成 CH ₄和 CO的活性催化剂。通过掺杂 Ga，我们成功地将这些催化剂的选择性几乎完全转向 CO。原位IR 光谱研究表明，该催化剂活性与负责吸附 CO ₂的表面羟基浓度直接相关以及在催化剂表面形成中间体碳酸氢盐和甲酸盐。Ga的添加改善了Ni分散，伴随着在氧化铝表面上形成Ni-Ga层，从而降低了表面羟基浓度。中间产物（即碳酸氢盐和甲酸盐）与催化剂表面之间的相互作用减少和减弱，将 CO 选择性从 40% 提高到 98%。