Comprehension of the Synergistic Effect between m&t-BiVO(4)/TiO(2)-NTAs Nano-Heterostructures and Oxygen Vacancy for Elevated Charge Transfer and Enhanced Photoelectrochemical Performances

Through the utilization of a facile procedure combined with anodization and hydrothermal synthesis, highly ordered alignment TiO(2) nanotube arrays (TiO(2)-NTAs) were decorated with BiVO(4) with distinctive crystallization phases of monoclinic scheelite (m-BiVO(4)) and tetragonal zircon (t-BiVO(4)), favorably constructing different molar ratios and concentrations of oxygen vacancies (V(o)) for m&t-BiVO(4)/TiO(2)-NTAs heterostructured nanohybrids. Simultaneously, the m&t-BiVO(4)/TiO(2)-NTAs nanocomposites significantly promoted photoelectrochemical (PEC) activity, tested under UV–visible light irradiation, through photocurrent density testing and electrochemical impedance spectra, which were derived from the positive synergistic effect between nanohetero-interfaces and V(o) defects induced energetic charge transfer (CT). In addition, a proposed self-consistent interfacial CT mechanism and a convincing quantitative dynamic process (i.e., rate constant of CT) for m&t-BiVO(4)/TiO(2)-NTAs nanoheterojunctions are supported by time-resolved photoluminescence and nanosecond time-resolved transient photoluminescence spectra, respectively. Based on the scheme, the m&t-BiVO(4)/TiO(2)-NTAs-10 nanohybrids exhibited a photodegradation rate of 97% toward degradation of methyl orange irradiated by UV–visible light, 1.14- and 1.04-fold that of m&t-BiVO(4)/TiO(2)-NTAs-5 and m&t-BiVO(4)/TiO(2)-NTAs-20, respectively. Furthermore, the m&t-BiVO(4)/TiO(2)-NTAs-10 nanohybrids showed excellent PEC biosensing performance with a detection limit of 2.6 μM and a sensitivity of 960 mA cm(−2) M(−1) for the detection of glutathione. Additionally, the gas-sensing performance of m&t-BiVO(4)/TiO(2)-NTAs-10 is distinctly superior to that of m&t-BiVO(4)/TiO(2)-NTAs-5 and m&t-BiVO(4)/TiO(2)-NTAs-20 in terms of sensitivity and response speed.