Highly selective CO2-to-CH4 conversion via an interfacial charge transfer-optimized 2D/2D Bi2MoO6/ZnIn2S4 S-scheme heterophotocatalyst under visible light illumination

초록

To address rising CO2 levels and the ongoing global energy crisis, sustainable and efficient CO2 conversion strategies are urgently required to transform CO2 into valuable fuels. This study presents an advanced 2D/2D Sscheme heterostructure photocatalyst, composed of ZnIn2S4 (ZIS) and Bi2MoO6 (BMO), synthesized via a controlled hydrothermal process. The composition-optimized BMO-20/ZIS heterostructure displayed a remarkable methane production rate of 95.2 mu mol g-1 h-1 and a quantum efficiency of 0.74 % at 400 nm, surpassing both individual components and previously reported catalysts. Notably, BMO-20/ZIS achieved 99 % selectivity for CH4 production while effectively suppressing competitive H2 evolution. In addition to its high activity, the BMO-20/ZIS catalyst demonstrated excellent stability and reusability, underscoring its potential for long-term, sustainable CO2 reduction. The superior photocatalytic efficiency is attributed to the synergistic interaction between ZIS and BMO, which enables effective visible-light absorption, increases surface area, and improves CO2 adsorption capacity. The well-aligned 2D/2D face-to-face interface facilitates efficient charge carrier mobility and spatial charge separation, while offering abundant active sites for CO2 conversion. Mechanistic investigations confirm the formation of an S-scheme heterojunction, which efficiently inhibits electron-hole recombination and preserves strong redox potentials, thereby enabling efficient and selective CH4 production. This study represents a significant advancement in the design of promising and durable photocatalysts for CO2 reduction, offering a promising pathway toward carbon-neutral energy solutions.

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