Development of glucose/H₂O₂ photocells using W-BiVO₄/V₂O₅ based photoanodes for electricity generation

Currently, there is a growing concern about the environmental impacts associated with the use of fossil fuels, which added to the energy crisis that has been increasing has challenged researchers in the development of unconventional energy sources. In this context, in recent years, researches related to the use of sugarcane bagasse have increased mainly focused on the production of second-generation ethanol (E2G). However, it is interesting to diversify energy options for the use of glucose from the sugarcane bagasse hydrolysate. In this sense, photofuel cells (PFC) have attracted interest due to their ability to harness solar energy and biomass energy simultaneously to generate electricity. Thus, the use of photoanodes based on the W-BiVO₄/V₂O₅ semiconductor has recently been presented as an alternative in photoelectrochemical devices. Different strategies were used to achieve the physical improvement of the semiconductor material and high density of photocurrent in the device. In this sense, the use of hole scavengers that can be used as fuel in PFCs are an alternative, which in addition to the physical improvements of the semiconductor, can increase the photocurrent and, consequently, improve the performance parameters of the PFCs. This research aims to development a PFC, capable of harnessing glucose (Glc) and H₂O₂, with the purpose of generating electricity to be used in electrical devices. The research methodology is based initially on the synthesis and characterization of the W-BiVO₄/V₂O₅ semiconductor, subsequently, photoelectrochemical tests seek to achieve optimal photocurrent generation parameters. Finally, the best systems based on the use of Glc and H₂O₂ were tested to evaluate the performance parameters of the PFC, from which the robust test can be performed and propose a system in configurations of 1.5 V and 12 V, aiming at the generation of electricity. Xe lamp, 100 mW cm^-2 , was used for the experiments. The results show that the use of Glc and H₂O₂ alone significantly increased the photocurrent generation by 103% and 46% respectively in reference to the use of the blank sample. On the other hand, when Glc/H₂O₂ is used simultaneously, a synergy is achieved that allows the photocurrent generation to be potentiated due to cleaning holes, oxidation of Glc and consequently electron injection to the system, allowing an increase in the photocurrent of 1700%. Based on these results, performance parameters of a PFC, open circuit voltage, Voc of 0.48 V, short circuit current, Jsc of 9.28 mA cm^-2 , PFC power, Pmax of 1.16 mW cm^-2 , with an efficient conversion of solar energy into electric energy, η of 1.16%, which is much higher than the research involving the use of glucose as a fuel. (author)