Integrating plasmon and vacancies over oxide perovskite for synergistic CO₂ methanation

The photocatalytic reduction of CO₂ to CH₄ offers a promising path for sustainable energy conversion, but its complexity, requiring an eight-electron transfer, poses significant challenges. This study presents a novel method to enhance the activity and selectivity of this reaction using Ag nanoparticles as cocatalysts on a mesoporous perovskite semiconductor, NiTiO₃. By leveraging the synergistic effects of localized surface plasmon resonance (LSPR) and strategically engineered vacancies, the Ag-NiTiO3 catalyst achieves a 15-fold increase in CH₄ production and near-perfect selectivity, up from 92.4 % in pristine NiTiO₃. Advanced simulations, including finite-difference time-domain (FDTD) and density functional theory (DFT), highlight the crucial role of LSPR-induced local electric fields and vacancies in enhancing methane selectivity. The integration of Ag nanoparticles into the NiTiO₃ matrix not only facilitates efficient electron-hole separation but also promotes the formation of vacancies essential for the CO₂ to CH₄ conversion. This work offers profound insights into the interaction between light, plasmonic materials, and semiconductor properties, providing a robust platform for optimizing photocatalytic performance. These findings advance our understanding of photocatalytic CO₂ reduction mechanisms, paving the way for designing more efficient and selective photocatalysts, contributing to broader CO₂ utilization strategies and addressing global carbon emissions and energy challenges.