Solar H2 production by a perovskite/silicon tandem cell using urea oxidation†

Abstract

Transition metal-based catalyst layers for hydrogen evolution (HER) and urea oxidation (UOR) are coupled to a perovskite/silicon (PK/Si) tandem photovoltaic (PV) cell and tested for H₂ production from urea-rich alkaline electrolytes under simulated sunlight. Results show that UOR significantly boosts H₂ evolution performance by allowing operation at the maximum power point of the PK/Si PV under solar illumination, which is not the case when the oxygen evolution reaction (OER) occurs. This assembly maintains stable performance over two days. The high concentration of produced NO₂⁻ confirms the occurrence of urea overoxidation pathways during UOR.