Unraveling Surface Polarization in Hydrothermally Derived AgFeO2 Nanosheets for Enhanced Photoelectrochemical Performance

Abstract

This study presents a comprehensive investigation into the synthesis and photoelectrochemical performance of delafossite AgFeO2 nanosheets, modulated through controlled hydrothermal conditions. The nanosheets' dimensions, specifically width and thickness, were tailored to examine the influence of surface polarization on photocatalytic efficacy. Notably, an increase in nanosheet width, while maintaining a constant thickness, corresponded to a significant rise in photocurrent density, peaking at 15.6 μA/cm² for AgFeO2 nanosheets with smaller thickness and larger surface area of (001) facet under optimized conditions. This enhancement is attributed to the increased intensity and contribution of the built-in electric field on the (001) polar facet, thus facilitating improved effective separation and rapid transfer of photogenerated electron-hole pairs. The introduction of interstitial oxygen and an external magnetic field further demonstrated the potential of multiple polarization coupling—spin, macro, and surface—to maximize the photoelectrochemical potential of AgFeO2 nanosheets. These findings underscore the critical role of surface polarization in optimizing the photoelectrochemical performance of AgFeO2 nanosheets and highlight the potential for nanoscale design in developing advanced photocathodes. The findings pave the way for future research aimed at refining synthesis methods and exploiting the synergistic effects of multiple polarizations for enhanced solar energy conversion efficiencies.