(378b) Heterostructured Cu2O/CuO Decorated with Nickel As a Photocathode for Photoelectrochemical Water Splitting

The design, synthesis and characterization of a novel Cu₂O/CuO heterojunction decorated with nickel cocatalyst as a highly efficient photocathode for solar hydrogen production was investigated. Due to the heterojunction synergism, the Cu₂O/CuO gave a remarkably improved photocurrent density (-2.1 mA/cm²), i.e. 3.1 times higher than a Cu₂O photoelectrode. Additionally, the Cu₂O/CuO heterojunction, when decorated with nickel cocatalyst, showed six-fold and two-fold increases in photocurrent density (-4.3 mA/cm²) respectively when compared to Cu₂O and bare Cu₂O/CuO at 0 V vs. RHE. Interestingly, the surface modification with Ni not only effectively promotes water splitting but also stabilizes the photoelectrode. The enhanced photoelectrochemical performance is attributable to the efficient charge transfer and protective role of Ni, the improved crystallinity and the synergism effect of the heterojunction in light absorption and charge separation. This inexpensive photocathode with increased photocurrent density and photostability offers a higher promise for solar hydrogen production.