AG, K. R.; Minja, A. C.; Chinnabathini, V. C.; Ninakanti, R.; Kumar, A. K. S.; Papamichail, D.; Grandjean, D.; Janssens, E.; van de Krol, R.; Verbruggen, S. W.: Nickel–Iron Clusters on Bismuth Vanadate for Efficient Photoelectrochemical Water Splitting. Advanced Functional Materials early view (2026)
10.1002/adfm.202526674
Abstract:
In this study, an ultrathin catalytic layer of nickel–iron (NiFe) nanoclusters is deposited onto an electrodeposited bismuth vanadate (BiVO4) photoanode via pulsed laser ablation. The nanoclusters are synthesized from bimetallic NixFe1-x (x = 0.25, 0.5, 0.75) alloy targets, resulting in cluster loadings between 0.55 and 1.74 µg cm−2, equivalent to 3–9 atomic monolayers. By varying the atomic Ni:Fe ratio (25:75, 50:50, and 75:25), both photoelectrochemical (PEC) activity and stability are optimized while minimizing total catalyst loading on pristine BiVO4. The BiVO4 photoanode with 6 atomic monolayer equivalents of Ni0.75Fe0.25 (1.16 µg cm−2) delivers a photocurrent density of 3.1 mA cm−2 at 1.23 V versus RHE, a 2.05-fold improvement over pristine BiVO4 (1.51 mA cm−2), along with a sixfold increase in applied bias photon-to-current efficiency (ABPE) reaching 1%. To assess robustness, both pristine and 6-Ni0.75Fe0.25BiVO4 are evaluated under variable electrolyte temperature (∼6°C–≥60°C) and concentrated illumination (1–6 suns). Under all tested conditions, the Ni0.75Fe0.25BiVO4 exhibits improved PEC performance and operational stability. These findings highlight the effectiveness of ultrathin (<1.7 µg cm−2) NiFe nanoclusters in significantly enhancing PEC performance and operational stability of BiVO4 photoanodes across a range of challenging operational conditions.