Photoelectrochemical Performance Improving Mechanism: Hybridization Appearing at the Energy Band of BiVO₄ Photoanode...

Surface passivation of the photoelectrode by wide bandgap semiconductor quantum layer is an important strategy to improve work stability and surface state inhibition. However, an inevitable energy barrier is generated during the quantum tunneling process of the photocarriers. To overcome this shortage, a tandem photo-generated hole transfer route is fabricated on BiVO₄ photoanode by doped dual-quantum layers modification, Ni-ZnO (5 nm) and Rh-SrTiO₃ (≈10 nm). Modulated photoelectrochemical (PEC), Scanning Kelvin Probe (SKP), and DFT calculation method results indicate that a tandem hole ohmic contact route is formed in the photoanode to reduce the quantum tunneling energy barrier, meanwhile, the photon absorption capacity of BiVO₄ is improved after doped quantum layers modification. Both a phenomenal attribute to the energy band hybridization between Ni, Rh 3d orbits in quantum layers with BiVO₄ photoanode. Then, the modified BiVO₄ photoanode achieves the recoded photocurrent density of 6.47 and 5.18 mA cm^-2 (Na₂ SO₃ electrolyte, V_RHE  = 1.23 V) under simulated sun light (100 mW cm^-2 AM 1.5 G) by xenon lamp illumination without and with UV composition cutting down to ≈5%, respectively. Generally, this work will highlight a potential application in the fields of PEC water splitting and photovoltaic conversion for various semiconductor nanomaterials.