Single-atomic ruthenium coupling with NiFe layered double hydroxide in-situ growth on BiVO₄ photoanode for boosting photoelectrochemical water splitting

Abstract

In the present work, NiFe layered double hydroxide (LDH) supported single Ru atoms in-situ growth on BiVO₄ photoanode (BiVO₄@NiFe-LDHs/Ru) was fabricated to enhance the photoelectrochemical (PEC) water splitting. Ru atoms anchored to NiFe-LDHs via oxygen coordination to form Ru-O-M bonds, which induced electrons rearrangement to improve charge carriers separation and injection. Combining with the synergistic effect of Ru and NiFe-LDHs, BiVO₄@NiFe-LDHs/Ru achieves high photocurrent density of 4.65 mA/cm² at 1.23 V vs. RHE. Besides, Ru atoms induced formation of V⁽⁵⁻ˣ⁾⁺ to stabilize V atoms in the lattice of BiVO4, which avoided V5+ dissolution during PEC water oxidation process. Density functional theory (DFT) calculation indicates that Ru SAs anchored to BiVO₄@NiFe-LDHs decrease the reaction energy barrier of rate-limiting step (*O → *OOH), resulting in acceleration of OER process. This work provides an effective pathway to design high efficient and stable photoanodes with single atoms for feasible PEC water splitting application.