Enhanced Activity and Stability of Carbon-Decorated Cuprous Oxide Mesoporous Nanorods for CO₂ Reduction in Artificial Photosynthesis

The development of photocatalysts with superior activity and stability to produce organic fuels through CO2 reduction under renewable sunlight is of great significance due to the depletion of fossil fuels and severe environmental problems. In this study, we presented a “hitting three birds with one stone” strategy to synthesize carbon layer coated cuprous oxide (Cu2O) mesoporous nanorods on Cu foils via a facile chemical oxidation and subsequent carbonization method. The thin carbon layer not only works as a protective layer to quench the common photocorrosion problem of Cu2O but also endows the sample a mesoporous and one-dimensional nanorod structure, which can facilitate reactant molecule adsorption and charge carrier transfer. Substantially, the coated samples exhibited remarkably improved stability as well as decent activity for CO2 reduction under visible light irradiation. The optimized sample attained an apparent quantum efficiency of 2.07% for CH4 and C2H4 at λ0 400 nm, and 93% activity remained after six photoreduction cycles under visible light. This work provides a facile strategy to address the stability and activity issues of Cu2O under visible light irradiation, which is presumably suitable for other semiconductors as promising candidates for CO2 reduction in artificial photosynthesis.