SCatSMCH: Rational design of Surface Catalytic Sites on defective MoOx/Mo2N heterostructure for CO2 Hydrogenation

CO2 hydrogenation has emerged as one of the most promising approaches to mitigating greenhouse effect by conversing CO2 into value-added chemicals. The efficiency of CO2 hydrogenation is largely determined by CO2 activation. Compared to the H2-assisted activation of CO2, the dissociative activation of CO2 (CO2->CO*+O*) with simplified reaction mechanism is significant for upgrading CO2 hydrogenation routes and existing catalysts, while it faces great challenges due to the chemical inertness of CO2. The researcher proposes that by utilizing the reduced formation energy of oxygen vacancies in MoO3/Mo2N heterostructure, an oxygen vacancy-rich defective MoOx (x<3) surface can be constructed to directly cleavage the stable C=O double bond in CO2 via modulating the concentration of oxygen vacancies and the electron donating capacity of exposed Mo sites. Afterwards, this supported metal-free MoOx/Mo2N catalyst will be used to catalyze the selective hydrogenation of CO2 to CO, known as the reverse water gas shift (RWGS) reaction. Based on the promoted dissociative activation of CO2, the supported metal-free MoOx/Mo2N catalyst is expected to achieve a combination of high conversion, high selectivity and low cost. In addition, by integrating Cu sites with enhanced H2 activation ability and defective MoOx surface with strong CO2 dissociation capacity, tandem Cu/MoOx/Mo2N catalysts will be proposed to efficiently catalyze low-temperature CO2 hydrogenation to CH3OH. The trade-off between catalytic activity and selectivity will be optimized by regulating the size of Cu species. The key structural descriptor for the RWGS reaction and methanol synthesis will be identified by comprehensive in situ/operando characterization techniques combined with density-functional theory calculations. The obtained results in this project will contribute to the early realization of carbon neutrality in the EU and the resolution of the energy crisis.