Effects of activation overpotential in photoelectrochemical cells considering electrical and optical configurations

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 ([Formula: see text]) required for splitting water. This work analyzes the impact of [Formula: see text] on solar-to-fuel efficiency ([Formula: see text]) 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 [Formula: see text] and HPR for different electrical and optical PEC configurations. Significant changes are observed in [Formula: see text] and HPR when [Formula: see text] is considered in water splitting.