Correlating Oxidation State and Surface Ligand Motifs with the Selectivity of CO2 Photoreduction to C2 Products

The design for non-Cu-based catalysts with the function of producing C2+ products requires systematic knowledge of the intrinsic connection between the surface state as well as the catalytic activity and selectivity. In this work, photochemical in situ spectral surface characterization techniques combined with the first principle calculations (DFT) were applied to investigate the relationships between the composition of surface states, coordinated motifs, and catalytic selectivity of a titanium oxynitride catalyst. When the catalyst mediates CO2 photoreduction, C-2 product selectivity is positively correlated with the surface Ti2+/Ti3+ ratio and the surface oxidation state is regulated and controlled by coordinated motifs of N-Ti-O/V[O], which can reduce the potential dimerization energy barriers of *CO-CO* and promote spontaneous formation of the subsequent *CO-CH2* intermediate. This phenomenon provides a new perspective for the design of heterogeneous catalysts for photoreduction of CO2 into useful products.

Automated summary

This study investigates the relationships between surface state composition, coordinated motifs, and catalytic selectivity of a titanium oxynitride catalyst using photochemical in situ spectral surface characterization techniques and first principle calculations (DFT). It is found that the C-2 product selectivity in CO2 photoreduction is positively correlated with the surface Ti2+/Ti3+ ratio and regulated by coordinated motifs of N-Ti-O/V[O], which can reduce energy barriers and promote the formation of *CO-CH2* intermediate. This provides a new perspective for the design of heterogeneous catalysts for CO2 photoreduction.