Structural engineering hematite photoanode composited with metal–organic framework heterojunction and Ru/MnOx cocatalyst to boost photoelectrochemical water oxidation

Abstract

Developing new photoanode materials with high catalytic activity and stability can notably improve the performance of photoelectrochemical water splitting (PEC-WS). Composite metal cocatalysts can combine the benefits of metals and metal oxides to obtain an efficient PEC-WS property of hematite (α-Fe2O3) photoanode. The FTO/α-Fe2O3/MOF/Ru/MnOx photoanode, constructed with a metal–organic framework (MOF) and noble metal/metal oxide (Ru/MnOx), possesses a high photocurrent density (1.93 mA/cm2), marking a significant 1.54-fold improvement over the pure α-Fe2O3 photoanode. Comprehensive mechanism studies elucidate that the Ru elements anchored on the α-Fe2O3/MOF heterojunctions provide more active sites, and the introduced MnOx catalyst can stabilize the Ru catalyst and improve the catalytic activity. The synergistic effect between α-Fe2O3/MOF heterojunction and Ru/MnOx cocatalyst further effectively improves the photogenerated carrier transport.