Nano multi-layered HfO/α-FeO nanocomposite photoelectrodes for photoelectrochemical water splitting.

This study marks a significant stride in enhancing photoelectrochemical (PEC) water splitting applications through the development of a type II nano-heterojunction comprising HfO and α - FeO. Fabricated via Physical Vapor Deposition/Radio Frequency (PVD/RF) sputtering, this nano-heterojunction effectively addresses the efficiency limitations inherent in traditional α - FeOphotoanodes. The integration of HfO leads to a substantial increase in photocurrent density, soaring from 62 μA/cm for pure α - FeO to 1.46 mA cm at 1.23 V versus the Reversible Hydrogen Electrode (RHE). This enhancement, a 23-fold increase, is primarily attributed to the improved absorption of photons in the visible range and the facilitation of more efficient charge transfer. The enhanced performance and long-term stability of the HfO/α - FeO nano-heterojunction, validated through XRD, XPS, Raman Spectroscopy, EDS, SEM, EIS, and UPS analyses, demonstrate its potential as a promising and cost-effective solution for PEC water splitting applications, leveraging renewable energy sources.