Electronic state reconfiguration of oxygen-doped carbon nitride covalently linked resorcinol-melamine-formaldehyde photocatalysts for highly selective CO2 reduction to methanol

The homogeneous electronic state on the surface and the lack of precise electronic state modulation strategies of carbon-based metal-free semiconductor photocatalysts hinder the efficient photocatalytic reduction of CO2. Here, one electronic state reconfiguration strategy was proposed to develop a non-metal catalyst consisting of resorcinol-melamine-formaldehyde (M) covalently connected to O-doped carbon nitride (OCN) for yielding methanol with high selectivity. The metal-free composite catalyst (O-M) exhibited an excellent methanol production rate of 22.27 μmol g−1 h−1, approximately 50 and 3 times higher than that of OCN and M, respectively. Spectroscopic analysis and theoretical calculation revealed that the constructed covalent bond between OCN and M served as an electron channel for rapid electron transfer. Based on these electron channels, introducing O broke uniform electron distribution and led to electronic state reconfiguration on the surface of O-M, which accelerated charge transfer and improved CO2 photoreduction. This work provides valuable insights into significantly improving photocatalytic performance through the modulating the electronic state of carbon-based metal-free photocatalyst.