Site-Specific Electron-Driving Observations of CO2-to-CH4 Photoreduction on Co-Doped CeO2/Crystalline Carbon Nitride S-Scheme Heterojunctions

Photoexcited dynamic modulation, maximizing the effective utilization of photoinduced electron-hole pairs, dominates the multiple electrons-involving reduction pathways for terminal CH4 evolution during CO2 photoreduction. Yet, the site-specific regulation of directional charge transfer by modification of an S-scheme heterojunction has seldom been discussed. Herein, an atomic-level tailoring strategy by anchoring single-atomic Co into CeO2 co-catalyst rather than carbon nitride supports, which can selectively favor CO2-to-CH4 photoreduction, is reported. Through in situ dynamic tracking investigations, this study identifies that surface Co-embedded bimetallic CeCo conjunction is the key feature driving a strong interconnection of dynamical charge states through S-scheme heterojunctions. The Co-embedded modification into CeO2 co-catalysts is demonstrated to have a critical effect on directional charge control, accelerating the driving of electrons from the carbon nitride donations to site-specific Co hubs, which thereby promotes electronic transferability for electrons-involving CH4 formation. As a result, an unprecedented CH4 yield (181.7 mu mol g(-1)) is obtained with a high turnover number (411.4) through a fully gas-solid reaction, demonstrating its potential toward targeted CH4 formation without adding any sacrificial agent.

Automated summary

This study reports a method of controlling directional charge transfer by embedding single-atomic Co into CeO2 catalyst to achieve selective CO2 photoreduction to CH4. The results show that Co embedded into CeO2 catalyst can accelerate the transfer of electrons from carbon nitride to specific Co sites, thereby promoting CH4 formation. This method achieves high yield and high turnover number of CH4 production without the need for any sacrificial agent.