Strategic band alignment of zinc oxide photoanode with fibrous silica framework for enhanced photoelectrochemical water splitting efficiency

Abstract

The urgent need to address both energy demand and environmental concerns has led to the exploration of solar energy utilization in photoelectrochemical (PEC) water splitting. The novelty of fibrous silica zinc oxide photoanode (FSZn) was introduced in this groundbreaking study, synthesized using the meticulous microemulsion method. Our investigation reveals the exceptional properties of FSZn using a comprehensive range of analytical techniques, including FESEM, FTIR, XRD, UV–Vis/DRS TEM, and N2 adsorption–desorption tests. The distinctive features of FSZn arise from its intricate bicontinuous concentric lamellar structure, resulting in a narrow bandgap and a vast surface area. Notably, FSZn exhibits a remarkable photocurrent density of 17.88 mA/cm2, surpassing that of conventional ZnO, which only yields 6.28 mA/cm2. Furthermore, FSZn achieves an impressive solar-to-hydrogen (STH) efficiency of 22.0 %. The favourable alignment of FSZn’s conduction band with the hydrogen reduction potential, which facilitates swift and efficient charge transfer processes conducive to spontaneous hydrogen generation, is responsible for this remarkable performance. The successful development of FSZn represents a significant milestone, offering valuable insights for advancing high-performance photoanodes. By significantly enhancing the efficiency of photoanodes in PEC water splitting processes, FSZn holds promise for accelerating the transition towards sustainable energy solutions.