Integrating plasmon and vacancies over oxide perovskite for synergistic CO₂ methanation

Abstract

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.