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

Abstract

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 µmol 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.