Long‐Lived, Visible‐Light‐Excited Charge Carriers of TiO₂/BiVO₄ Nanocomposites and their Unexpected Photoactivity for Water Splitting

Abstract

Different mole ratios of TiO 2 /BiVO 4 nanocomposites with effective contacts have are fabricated by putting BiVO 4 nanoparticles into the TiO 2 sol, followed by thermal treatment at 450 °C. Based on the transient‐state surface photovoltage responses and the atmosphere‐controlled steady‐state surface photovoltage spectra, it is concluded that the photogenerated charge carriers in the TiO 2 /BiVO 4 nanocomposite with a proper mole ratio (5%) display much longer lifetime and higher separation than those in the BiVO 4 alone. This is responsible for the unexpected activity for photoelectrochemical oxidation of water, for photocatalytic production of H 2 , and for photocatalytic degradation of phenol as a model pollutant under visible irradiation. Moreover, it is suggested that the prolonged lifetime and increased separation of photogenerated charges in the fabricated TiO 2 /BiVO 4 nanocomposite is attributed to the unusual spatial transfer of visible‐excited high‐energy electrons of BiVO 4 to TiO 2 . This work will provide feasible routes to synthesize visible‐light responsive nanomaterials for efficient solar utilization.