Experimental investigation and energetic and exergetic evaluations of newly designed photocathodes for solar hydrogen production system
Energy, vol.362, 2026 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 362
- Publication Date: 2026
- Doi Number: 10.1016/j.energy.2026.142166
- Journal Name: Energy
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Applied Science & Technology Source, Compendex, Environment Index, Geobase, INSPEC, Public Affairs Index, Academic Search Ultimate (EBSCO), Engineering Source (EBSCO)
- Keywords: Efficiency, Energy, Exergy, Fuel, Hydrogen, Solar energy, Sustainability
- Yıldız Technical University Affiliated: Yes
Abstract
In this study, a novel and efficient solar-to-hydrogen energy conversion system based on photoelectrochemical (PEC) water splitting is developed as a promising alternative within the evolving energy ecosystem where hydrogen serves as a sustainable fuel, a key feedstock, and an energy storage medium. Hydrogen production is experimentally investigated in a specifically designed PEC reactor for the dimensions of the photoelectrodes. The developed photocathodes are based on an unconventional brass substrate, on the surface of which photoresponsive layers such as Cu2O and ZnO naturally exist. TiO2 doped with Ir and Mo, both individually and in a co-doped combination, is deposited on this surface via spin- and dip-coating methods. The photoelectrocatalysts are synthesized using the sol–gel method, and doping with Ir (1%, 3%, and 5%), Mo, and Ir–Mo combinations is employed to improve PEC performance. The photocathodes are evaluated through energy efficiency, exergy efficiency, applied bias photon-to-current efficiency (ABPE), and hydrogen yield. The highest hydrogen production rate of 59.98 μmol/cm2h is achieved with 1% Ir-doped TiO2 deposited via dip coating, and its energy, exergy and ABPE efficiencies are found to be 4.03%, 4.14%, and 0.49%, respectively. More importantly, the use of a non-traditional brass substrate leads to an unexpected observation, where an inversion in behavior is identified, which reveals the critical role of the substrate's natural surface oxide layers and substrate-induced interfacial effects in PEC performance.