AlOOH nanosheets modified Ti-Fe2O3 with oxygen vacancies for highly efficient photoelectrochemical water splitting

Effective co-catalysts are demanded to unveil the complete photoelectrochemical efficacy of the Ti-Fe2O3 photoanode for water splitting. This work introduces nanosheet-structured AlOOH (AlOOH-ns) on Ti-Fe2O3 by in situ synthesis for utilization as a co-catalyst. The abundant electrochemical active surface area of AlOOH-ns guarantees efficient hole transfer, demonstrating superior performance compared to amorphous AlOOH. Additionally, AlOOH-ns is insensitive to N2 treatment, enabling it to serve as a confining layer to bury the oxygen vacancies in Ti-Fe2O3 induced by N2 treatment within the bulk of AlOOH-ns/Ti-Fe2O3, thereby resulting in a high carrier density, facilitated bulk hole transport and separation and improved stability. Eventually, with a transition metal-centered co-catalyst, namely NiFeB hydroxide (NiFeB-hydx) to co-modify the photoanode, the NiFeB-hydx/AlOOH-ns/Ti-Fe2O3(N2) exhibits a brilliant photocurrent density of 3.41 mA cm-2 at 1.23 V versus the reversible hydrogen electrode (VRHE) with a low onset potential of 0.65 V RHE and an applied bias photon-to- current efficiency of 0.44 % at 0.94 V RHE .