A simple-structured enzyme-free photoelectrochemical sensor: Facile deposition of mesoporous BiVO₄ thin film for selective ascorbic acid detection with outstanding long-term stability

An enzyme-free photoelectrochemical (PEC) sensor with a simple structure and excellent stability was developed for the detection of ascorbic acid (AA). The sensing platform was constructed based on the in-situ preparation and deposition of a mesoporous BiVO₄ layer using an innovative technique. The sensor exhibited high selectivity, repeatability, and outstanding long-term stability, with a linear detection range of 0.5–430 μM and a detection limit of 0.13 μM. Notably, the sensor retained 93 % of its initial photocurrent after 90 reuse cycles over 90 days and 98 % of its photoactivity after 6 months of storage under ambient conditions, setting a benchmark performance among PEC sensors. The superior stability and sensing performance are attributed to the mesoporous electrode structure and strong adhesion of the BiVO₄ thin film to the substrate, facilitated by the unique deposition method, eliminating the need for further modifications or enzymatic additives.