Engineered Cobalt Single‐Atoms@BiFeO₃ Heteronanostructures for Highly Efficient Solar Water Oxidation

Abstract

Abstract Efficient charge–carrier separation and their utilization are the key factors in overcoming sluggish four‐electron reaction kinetics involved in photocatalytic oxygen evolution. Here, a novel study demonstrates the significance of Na 2 S 2 O 8 as a sacrificial agent in comparison to AgNO 3 . Resultantly, BiFeO 3 (BFO) and titanium doped‐oxygen deficient BiFeO 3 (Ti‐BFO‐R) nanostructures achieve ≈64 and 44.5 times higher O 2 evolution in the presence of Na 2 S 2 O 8 compared to AgNO 3 as a sacrificial agent, respectively. Furthermore, the presence of Co single atoms (Co‐SAs) deposited via immersion method on BFO and Ti‐BFO‐R nanostructures led to achieving outstanding O 2 evolution at a rate of 16.11 and 23.89 mmol g −1 h −1 , respectively, which is 153 and 227.5 times higher compared to BFO (in the presence of AgNO 3 ), the highest O 2 evolution observed for BFO‐based materials to date. The successful deposition of Co‐SAs is confirmed by aberration‐corrected high‐angle annular dark‐field scanning transmission electron microscopy (AC HAADF‐STEM) and X‐ray absorption near‐edge structure (XANES). The charge transfer investigations confirm the significance of Co‐SAs on BFO‐based photocatalysts for improved charge–carrier separation, transport, and utilization. This novel study validates the excellent role of Na 2 S 2 O 8 as a sacrificial agent and Co‐SAs as a cocatalyst for BFO‐based nanostructures for efficient O 2 evolution.