Bifunctional photoelectrochemical process for humic acid degradation and hydrogen production using multi-layered p-type Cu₂O photoelectrodes with plasmonic Au@TiO₂

Bifunctional photoelectrochemical (PEC) process for simultaneous hydrogen production and mineralisation of humic acid in water using TiO₂-1 wt% Au@TiO₂/Al₂O₃/Cu₂O multi-layered p-type photoelectrodes is demonstrated. The newly designed bifunctional PEC system leads to a high degradation efficiency of dissolved humic compounds, the target pollutant, by up to 87% during 2 h reaction time. Simultaneously, humic acid is also served as a sacrificial electron donor in the proposed system, contributing to a high photocurrent density of the multi-layered p-type Cu₂O photoelectrodes up to -6.32 mA cm⁻² at 0 V vs. Reversible Hydrogen Electrode (RHE) under the AM 1.5 simulated 1-Sun solar illumination. The Z-scheme feature of this bifunctional PEC devices exhibiting a short-circuit photocurrent density of -0.45 mA cm⁻² and solar-to-hydrogen conversion (STH) of 0.5 % in the presence of humic acid sheds light on the new bias-free artificial photosynthesis PEC system.