Plasmon aided (BiVO₄)_x–(TiO₂)_1−x ternary nanocomposites for efficient solar water splitting

The work presents the results of newly synthesized facile plasmon aided nanocomposite series, ((BiVO₄)_x–(TiO₂)_1−x, x = 0.01, 0.05, 0.10 and 0.20) for the efficient solar-driven water splitting application. Owing prominent optoelectrical properties of B10 = (BiVO₄)_0.10–(TiO₂)_0.90 composite, Ag nanoparticles (NPs) were impregnated to study the effect of surface plasmon resonance (SPR) phenomenon. A significant shift of 0.16° and 0.4 eV is recorded in X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) profiles, respectively which confirmed the formation of Ag/B10 nanocomposite. The micrograph and elemental mapping of Ag/B10 composite confirm a homogenous distribution of its components. A notable decrease in the band gap from 3.26 eV (TiO₂) to 2.44 eV (Ag/B10) is estimated by Kubelka − Munk equation. Furthermore, the substantial decrease in photoluminescence (PL) intensity of Ag/B10 (∼7 folds of TiO₂) corroborates its higher light absorption capacity and lower photo-excitons recombination. The photoelectrochemical (PEC) water splitting studies carried out via linear sweep voltammetry (LSV) demonstrate that all the photoanodes were active at ∼0.6 V. Whereas, chronoamperometry (I – t) results depicted the photocurrent density reached to the maximum value of ∼230 µA cm⁻² at 0.6 V for Ag/B10 under chopped solar irradiations. Moreover, B10 and Ag/B10 nanostructures affirm prolonged photocurrent (I – t) stability until 3600 s. We report here for the first time, Ag/B10 ternary composite shows enhanced photocurrent density due to its narrow band gap, lower photo-excitons recombination and SPR effect as compared to pristine TiO₂, BiVO₄ and their binary composites.