Synergetic integration of passivation layer and oxygen vacancy on hematite nanoarrays for boosted photoelectrochemical water oxidation

Abstract

To seek effective strategies that improve the photoelectrochemical water oxidation performance of hematite (α-Fe2O3) photoanodes is still challenging owning to their abundant surface states and low charge transfer efficiency. Herein, a facile impregnation method with an annealing process was developed to synthesize MoO3 modified Fe2O3 photoanodes using the MoO3 layer as an effective passivation component to decrease surface states and thus to improve the charge separation and transfer process at the electrode/electrolyte interfaces. The oxygen vacancies were subsequently introduced to steer the electrical conductivity, and further to boost the charge separation and transfer. The optimized MoO3-x/Fe2O3-x photoanode displays a photocurrent density of 2.6 mA cm–2 at 1.23 V versus the reversible hydrogen electrode under AM 1.5 G irradiation, 2.2 times that of the Fe2O3 (1.2 mA cm–2). The synergetic integration of passivation layer and oxygen vacancies on photoelectrodes heralds an efficient paradigm for solar energy conversion.