Combinational effect of NiFeOx/Tb(OH)x as hole extractor for enhanced charges separation and stability of BiVO4 photoanode for solar water splitting

Development of efficient and stable photoanodes for the efficient oxygen evolution reaction highly needs for photoelectrochemical (PEC) water splitting. Herein, we demonstrate terbium hydroxide (Tb(OH) x ) for significantly boosting the oxygen evolution activity and stability of NiFeO x /BiVO 4 photoanodes. The Tb(OH) x nanoparticles in NiFeO x /Tb(OH) x /BiVO 4 photoanode as hole extractor rapidly transfer holes from BiVO 4 to NiFeO x , effectively improving the bulk charge separation efficiency and water oxidation kinetic efficiency, thus improving the PEC performance. The resulting NiFeO x /Tb(OH) x /BiVO 4 photoanode achieves an excellent photocurrent density of 5.75 mA/cm 2 and excellent stability with 110 h at a potential 1.23 V versus reversible hydrogen electrode (RHE) under AM 1.5G illuminations. This work not only analyzes the role of Tb(OH) x as a hole extractor in the photoanode, but also provides a promising strategy for designing the efficient PEC photoanodes. • Tb(OH) x nanoparticles was used as hole extractor. • The NiFeO x /Tb(OH) x /BiVO 4 photoanode achieves a superior photocurrent density and stability. • The bulk charge separation efficiency and water oxidation kinetic efficiency are improved.