Double-shelled Cu₂O/MnO_x mesoporous hollow structure for CO₂ photoreduction with enhanced stability and activity

Photocatalytic CO₂ reduction reaction (CRR) represents a prospective route for the clean utilization of greenhouse gas CO₂ and solar energy, and cuprous oxide (Cu₂O) is a favourable material for the CRR to avoid excess generation of hydrogen through the competitive hydrogen evolution reaction (HER). However, the application of Cu₂O-based photocatalysts is limited by their poor stability and low activity, which result from the self-corrosion by photogenerated holes. Here we construct a double-shelled Cu₂O/MnO_x mesoporous hollow structure (D-CMH) to enhance the stability and activity of Cu₂O-based photocatalysts. Because of the thin shells, which can shorten the diffusion distance of charge carriers, and the oxidation cocatalyst MnO_x, which can efficiently attract holes, the photogenerated holes can be immediately removed from Cu₂O and react with reactants. Additionally, the D-CMH can also provide enhanced efficiency of charge separation, prolonged path of light scattering and reflection and enlarged surface area for active sites, which result in the initial activity enhanced by 7.1 times and stability enhanced by 11.2 times compared with benchmark Cu₂O nanoparticles.