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

• Published in: Applied catalysis. B, Environmental Environmental, 2021-05, Vol.284, p.119760, Article 119760
• Main Authors: Li, Hua-Min, Wang, Ze-Yuan, Jing, Hui-Juan, Yi, Sha-Sha, Zhang, Sheng-Xi, Yue, Xin-Zheng, Zhang, Zong-Tao, Lu, Hong-Xia, Chen, De-Liang
• Format: Article
• Language: English
• Subjects: Charge efficiency; Charge transfer; Electrical conductivity; Electrical resistivity; Electrodes; Energy conversion; Fe2O3 photoanode; Ferric oxide; Hematite; Integration; Interfaces; Irradiation; Molybdenum oxides; Molybdenum trioxide; MoO3 layer; Oxidation; Oxygen; Oxygen vacancy; Passivate surface states; Passivity; PEC water oxidation; Photoelectric effect; Photoelectric emission; Separation; Solar energy; Solar energy conversion; Surface charge; Vacancies
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2020.119760

The well-designed MoO3-x/Fe2O3-x photoanode exhibits superior PEC water oxidation performance due to the efficient charge separation and transport derived from the introduced MoO3 surface passivation layer and oxygen vacancy. [Display omitted] •Establishing passivation effect of MoO3 on Fe2O3 photoanode.•Collaboration of passivation layer and oxygen vacancy on Fe2O3 was designed.•The boosted charge separation and transport are achieved on modified photoanode.•Exhibiting superior water oxidation performance on MoO3-x/Fe2O3-x photoanode. 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.