Boosting CO₂ hydrogenation to C₂₊ hydrocarbons via phase modulation using a Ni-doped CuCo catalyst

The catalytic hydrogenation of CO₂ to C₂₊ hydrocarbons is one of the most promising routes to achieving carbon neutrality. However, the development of effective catalysts to promote this transformation is still a challenging task. This work modulates the phase composition of CuCo bimetallic oxide catalysts through Ni doping, thereby influencing the strong electronic interactions at the material's surface and interface. The Ni doping promotes the production of straight-chain C₂₊ hydrocarbons via CO₂ hydrogenation, without formation of oxygenates. Notably, the Ni_0.1Cu₁/CoO _x catalyst with Ni doping at a Ni : Cu ratio of 0.1 exhibits an impressive 63.0% selectivity for C₂₊ hydrocarbons during liquid-solid phase CO₂ hydrogenation at a low temperature of 200 °C. With the phase transformation during the Ni doping, the strong interactions between Cu oxide and Co oxide species are enhanced, and the electronic structures of Cu and Co are finely tuned. The strongly coupled heterointerfaces (i.e., Cu⁰/Cu⁺-CoO _x interfaces) and numerous active sites (such as Co²⁺-O_v-Co²⁺, Cu⁰/Cu⁺, Ni-O-Co and/or Co₂C) generated by this process may facilitate the formation of key *CO and *CH _x species, which are further converted into C₂₊ hydrocarbons. This study provides insights for optimizing Co-based catalysts for CO₂ hydrogenation.