The influence of Ni impurities on the structural phase of BiVO4 for enhanced binder-free voltammetric vanillin sensing, photocatalysis, and latent fingerprint studies

The creation of advanced materials for addressing contemporary challenges in environmental monitoring and forensic investigations, as well as in food quality assessment, is very important in the modern technology research field. Hence, there is a high demand for multifunctional materials with innovative designs. In this study, a facile technique is used to synthesize Ni-doped BiVO₄ (NBV) nanoparticles (NPs) using glucose as a reducing agent. The effect of doping and the structural transformation was studied by introducing different dopant percentages, such as 2%, 4%, 8%, and 10% Ni, into BiVO₄ (BV) and comparing the characteristic properties of BV using characterization techniques such as XRD, UV–vis, FT-IR, SEM, PEIS, and PL. With the addition of dopant Ni, a phase transformation of BiVO₄ occurs, retaining its original monoclinic phase while introducing another phase, such as tetragonal. This leads to the stabilization of a dual-phase system that alters the electrochemical and optical properties. The band gaps of the synthesized NPs are found to be in the range of 1.50–4.0 eV, with 4% Ni-doped BiVO₄ (4 NBV) showing a very low band gap of 1.57 eV. 4 NBV modified GCE shows a highly sensitive response for the detection of vanillin, with a detection limit of 99 nM and a sensitivity of 81.21 A/M, highlighting its versatility in analytical applications. The photoluminescence property of NPs at 488 nm highlights their optical properties with greenish-blue emission for optoelectronic devices as well as advanced forensic studies through the development of visible, well-defined latent fingerprints. 4 NBV exhibits excellent photocatalytic properties, demonstrating 100% efficiency in degrading organic contaminants such as methylene blue.