Nano multi-layered HfO2/α-Fe2O3 nanocomposite photoelectrodes for photoelectrochemical water splitting

Abstract

This study marks a significant stride in enhancing photoelectrochemical (PEC) water splitting applications through the development of a type II nano-heterojunction comprising HfO2 and α - Fe2O3. Fabricated via Physical Vapor Deposition/Radio Frequency (PVD/RF) sputtering, this nano-heterojunction effectively addresses the efficiency limitations inherent in traditional α - Fe2O3photoanodes. The integration of HfO2 leads to a substantial increase in photocurrent density, soaring from 62 μA/cm2 for pure α - Fe2O3 to 1.46 mA cm−2 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 HfO2/α - Fe2O3 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.