Accessing Strain Engineered V-Fe(O)OH from Prussian Blue Analogue Precatalyst for Efficient Anodic Oxidation...

Prussian blue analogues (PBAs) are promising precatalysts to access active metal oxyhydroxide [M(O)OH] phases for anodic oxidation reactions (AORs). In this study, we have introduced a d-d electron complementation strategy to fine-tune the electronic features of a VOFe-PBA precatalyst. Spectroscopic studies revealed the altered coordination and electronic features of the VOFe-PBA precatalyst compared to the FeFe-PBA counterpart. The electrochemical activation of the VOFe-PBA precatalyst led to the formation of a strained V-Fe(O)OH active catalyst. Notably, V-Fe(O)OH demonstrated exceptional performance, requiring a potential of only 1.56 V versus RHE for oxygen evolution reaction (OER) and 1.42 V versus RHE for iodide oxidation reaction (IOR) at a current density of 100 mA cm^-2, significantly outperforming the Fe(O)OH. When employed in IOR-assisted water splitting, V-Fe(O)OH achieved an energy efficiency of 60% compared to overall water splitting. In-situ Raman studies reflected the potential dependent generation of active reaction intermediates, which participated in IOR to produce iodate. Mechanistic investigations suggested the involvement of a lattice oxygen mechanism (LOM) facilitated by a proton-decoupled electron transfer (PDET) pathway.