The only strategy for reducing fossil fuel-based energy sources is to increase the use of sustainable ones. Among renewable energy sources, solar energy can significantly contribute to a sustainable energy future, but its discontinuous nature requires a large storage capacity. Due to its ability to be produced from primary energy sources and transformed, without greenhouse gas emissions, into mechanical, thermal, and electrical energy, emitting only water as a by-product, hydrogen is an effective carrier and means of energy storage. Technologies for hydrogen production from methane, methanol, hydrocarbons, and water electrolysis using non-renewable electrical power generate CO2. Conversely, employing photoelectrochemistry to harvest hydrogen is a sustainable technique for sunlight-direct energy storage. Research on photoelectrolysis is addressed to materials, prototypes, and simulation studies. From the latter point of view, models have mainly been implemented for aqueous-electrolyte cells, with only one semiconductor-based electrode and a metal-based counter electrode. In this study, a novel cell architecture was numerically modelled. A numerical model of a tandem cell with anode and cathode based on metal oxide semiconductors and a polymeric membrane as an electrolyte was implemented and investigated. Numerical results of 11% solar to hydrogen conversion demonstrate the feasibility of the proposed novel concept.This research was funded by the European Union’s Horizon 2020 research and innovation program under grant agreement ID 760930 (FotoH2 project)
