Effects of activation overpotential in photoelectrochemical cells considering electrical and optical configurations
Abdul Ahad Mamun, Asif Billah, Muhammad Anisuzzaman Talukder
Abstract
Photoelectrochemical cells (PECs) are a promising option for directly converting solar energy into chemical energy by producing hydrogen (H 2 ) gas, thus providing a clean alternative to consuming fossil fuels. H 2 as fuel is free from any carbon footprints and negative environmental impacts. Therefore, the H 2 production, especially directly using sunlight in PECs, is critically important for the rapidly growing energy demand of the world. Although promising, PECs are inefficient and must overcome a few inherent losses in producing H 2 —the most important being the activation overpotential ( η a ) required for splitting water. This work analyzes the impact of η a on solar-to-fuel efficiency ( η STF ) and H 2 production rate (HPR). This work also discusses choosing appropriate photo-absorbing materials based on their energy bandgaps and suitable electrode pairs to achieve desired η STF and HPR for different electrical and optical PEC configurations. Significant changes are observed in η STF and HPR when η a is considered in water splitting.