Exactly regulated copper catalysts exploiting isolated photoelectrochemical reduction of cuprous oxides and random mesh-structured TiO2 for enhanced photoelectrochemical CO2 conversion

초록

Photoelectrochemical (PEC) CO2 reduction for the direct conversion of solar energy into carbon-based chemical fuels has received considerable attention owing to it being an inherently sustainable and green process. However, complex photocathode architectures and processes involving protective layers and co-catalysts typically hinder product selectivity and stable PEC operation. Cu is the only electrocatalyst that yields products containing multiple carbon molecules during the electrochemical CO2 reduction reaction (CO2RR). In this study, Cu nanoparticles were artificially fabricated on the surface of Cu2O from a light absorption layer using isolated photoelectrochemical reduction, which was designed from a negative photocorrosive reaction. Using hydrogen evolution reaction (HER) and CO2RR electrolytes, HER-Cu (H-Cu) and CO2RR-Cu (C-Cu) catalysts were respectively fabricated by artificially controlling photoelectrochemical self-photocorrosion (SPC) at the atomic level. Additionally, we adopted a partially installed random-mesh (RM) structured protective TiO2 layer with ultimately thin thickness and the optimal structure displays resistant to photocorrosion by forming individual catalyst particles on the uncovered RM-TiO2. The designed Cu2O/RM-TiO2/H-Cu displays a remarkable cathodic-photocurrent density of -1.57 mA cm(-2) at 0.4 V-RHE, CO formation with 98% efficiency, and improved stability under illumination. The utilization of an RM-structured TiO2 layer mitigates loss of charge via recombination, while also imposing a physical barrier that restricts direct interaction between the Cu2O surface without the Cu catalyst and the electrolyte. This study provides mechanistic insights into the CO2RR pathways and suggests an innovative approach that exploits the intrinsic corrosion reaction to design efficient PEC CO-producing catalysts.

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