Deficient MoO2 facilitating photothermal synergetic catalytic CO2 reduction selectively to CO over P-doped g-C3N4

Abstract

Photocatalytic conversion of CO₂ into fuels is considered a promising solution to the climate crisis and fossil fuel depletion. However, most photocatalysts exhibit low CO₂ reduction performance because of poor carrier separation, limited light absorption, or insufficient surface active sites. In this study, we fabricated a direct Z-scheme heterojunction (X-MoO₂/PCN) using oxygen-deficient molybdenum dioxide (MoO₂) and phosphorus-doped graphitic carbon nitride (PCN). Phosphorus doping enhances light absorption of g-C₃N₄ (CN), while the localized surface plasmon resonance (LSPR) effect in oxygen-deficient MoO₂ activates photothermal synergistic catalysis. The heterojunction also facilitates efficient separation of photogenerated carriers. The optimized 15 %-MoO₂/PCN composite exhibited yield of CO and CH₄ up to 92.11 μmol/g/h and 0.85 μmol/g/h under Uv–Vis-IR irradiation with a CO selectivity highly to 99.10 %, higher than most of the reported g-C₃N₄-based materials. This work provided a novel approach towards the rational design of a Z-scheme heterojunction for efficient photothermal CO₂ reduction.