High-efficiency synergistic conversion of CO2 to methanol using Fe2O3 nanotubes modified with double-layer Cu2O spheres.

Cuprous oxide/hematite nanotubes (Cu2O/Fe2O3NTs) were prepared by a potentiostatic electrodeposited method, in which different structured Cu2O materials were modified onto Fe2O3 NTs surface. Among them, the material with double-layer Cu2O spheres (Cu2O/Fe2O3 NTs-30) showed excellent photoelectrocatalytic (PEC) properties with a suitable energy band gap (1.96 eV) and a smaller overpotential (0.18 V). Furthermore, Cu2O/Fe2O3 NTs-30 showed two types of synergisms in the PEC reduction of CO2: (i) between electrocatalysis and photocatalysis and (ii) between Cu2O and Fe2O3NTs. The faradaic efficiency and methanol yield reached 93% and 4.94 mmol L(-1) cm(-2) after 6 h, respectively.