Insights into Boosting Photoelectrochemical Performance Over Cu3(BTC)2 Passivated Cu2O Nanorod Arrays

Earth-abundant Cu2O is a promising photocathode material for photoelectrochemical (PEC) water splitting. However, the serious photocorrosion and low efficiency retard its practical applications. Herein, a porous Cu-based metal-organic framework material, Cu-3(BTC)(2), as surface passivation layer is grown on Cu2O nanorod arrays (NRARs) photocathode by in situ surface/interfacial growth. Compared to conventional Cu2O photocathodes, the optimized Cu2O/Cu-3(BTC)(2) NRARs exhibit two times higher photocurrent density, approximate to 2.73 mA cm(-2) at 0 V-RHE under visible light irradiation, and the maximum incident photon to converted electron (IPCE) performance reaches 45% (450 nm). It is demonstrated that the Cu-3(BTC)(2) layer synergistically passivates interfacial defects, forms p-n junctions at the Cu2O/Cu-3(BTC)(2) interface, and introduces active sites catalyzing the hydrogen evolution reaction (HER), improving charge separation, transfer, and utilization efficiency. Moreover, the oxidative Cu2O photocorrosion is inhibited owing to the accelerated charge dynamics at the Cu2O/Cu-3(BTC)(2) interface and the hole-scavenging ability of Cu-3(BTC)(2), meanwhile, reductive Cu2O photocorrosion at Cu2O/Cu-3(BTC)(2) is also attenuated by catalyzing the water reduction reaction that competes for photoelectrons and sustaining balanced Cu2+(Cu+)/Cu-0 cycles.

Automated summary

In this study, a porous Cu-based metal-organic framework material, Cu-3(BTC)(2), is grown on Cu2O nanorod arrays to overcome the issues of photocorrosion and low efficiency. The optimized Cu2O/Cu-3(BTC)(2) photocathode exhibits higher photocurrent density and improved incident photon to converted electron performance.