Deposition of ultrasmall Ru-doped V2O3 nanocrystals at nickel foam as self-supported binder-free electrode for efficient and sustainable alkaline hydrogen evolution reaction

Transition metal oxide (TMO)-based electrocatalysts for alkaline water splitting are often limited by poor conductivity, low active surface area, and sluggish reaction kinetics. Herein, a Ru–V 2 O 3 heterostructured thin film is directly deposited on nickel foam (NF) via a one-step aerosol-assisted chemical vapor deposition (AACVD) process. This method enables uniform growth and controlled incorporation of ultrasmall Ru (<5 at.%) into V 2 O 3 , producing 2–8 nm nanocrystals with abundant accessible active sites and enhanced charge transfer. The optimized Ru–V 2 O 3 /NF catalyst outperforms a benchmark 100% Ru catalyst (fabricated by AACVD), demonstrating strong synergy between Ru and the conductive V 2 O 3 matrix. Its binder-free 3D architecture ensures intimate interfacial contact and efficient electron transport without additives or post-treatment. The catalyst delivers −1000 mA cm −2 at 263 mV in 1.0 M KOH with a Tafel slope of 49.3 mV dec −1 , while requiring only 98 and 157 mV at −50 and −100 mA cm −2 , respectively. Excellent stability was maintained over 50 h.