Hydrogen-bond network mediated lattice-strain engineering for CO₂-to-CH₄ selectivity regulation via flame spray...

How to effectively improve the electron utilization rate and high selectivity of products in CO₂ photoreduction is a key challenge limiting photocatalytic applications. Herein, based on flame strategy, a CeO₂ multivesicular structure modified with -OH species and compressive lattice strain (-1.92 %) were in-situ constructed. In-depth research on electron behavior and catalytic pathways revealed that the synergistic effect of hydrogen bond networks and compressive lattice strain in CeO₂ photocatalysts could optimize band structures, photoelectric current stability, regulate surface electron behavior and selectivity of catalytic pathways, providing a kinetic basis for active surface catalytic reactions accelerating the process of multiple electrons conversion. Eventually, high yields and selectivity of CH₄ were achieved under gas-solid phase reactions without any photosensitizers or sacrificial agents, with an increase of 8.86 times in photoreduction yield, a CO₂-to-CH₄ selectivity as high as 80.4 %, and an electron utilization rate as 5.73 times enhancement. Notably, experimental and theoretical calculation results reveal that the formation of hydrogen bond networks by introducing -OH groups, which induces surface compressive lattice strain and directional electron flow, is a key factor in significantly improving CO₂ photoreduction performance. This work will provide new insights into the design of microstructures on material surfaces for high-performance photocatalysts.