Atomic activation triggering selective photoreduction of CO2 to CH4 over NiAl-LDH/CeO2 heterojunction

Driving efficient and accurate C-H or C-C coupling for CO2 conversion is still a daunting task due to its thermodynamic limitations and diversified products. The unsatisfactory solar-to-fuel conversion efficiency and poor product selectivity remain a major dilemma of its further application. Here, we proposed an atomic activation way to design a flower-like NiAl-LDH/CeO2 hybrid heterojunction for selective CH4 photosynthesis by decorating CeO2 nanoparticles on NiAl-LDH nanosheets. The calculated and experimental results showed that the electrons in the NiAl-LDH nanosheets would spontaneously migrate to CeO2 and hence form an internal electric field (IEF) directing from NiAl-LDH to CeO2, which could drive an S-scheme charge transfer in the NiAl-LDH/CeO2 upon visible-light illumination. Importantly, the decorated CeO2 nanoparticles could also optimize the electronic structure and activate the originally inert Ni and Al atoms on NiAl-LDH, serving as the potential active centrals. As a result, the NiAl-LDH/CeO2 S-scheme heterojunction unveiled a higher CH4 yield rate of 16.33 μmol g−1 h−1 with a high selectivity of exceeding 90.0% comparing with pristine NiAl-LDH and CeO2 materials. This work highlights an atomic activation technique to design LDH-based heterogeneous photocatalysts, which unveils a new vision to develop efficient hybrid material systems for CO2 conversion applications.