Green and Solvent-Free Synthesis of Cu–Nb Composites Decorated with Platinum Nanoparticles for Hydrogen Evolution from NH ₃ BH ₃

The global search for sustainable energy sources has placed H2 production at the center of clean energy research. In this work, niobium-based material decorated with platinum nanoparticles (Pt NPs) was synthesized and applied as catalysts for H2 evolution through the hydrolysis of ammonia borane (NH3BH3). The supports were prepared by a mechanochemical route, followed by Pt NPs deposition, and characterized by FTIR, XRD, Raman, TEM, EDS, and XPS analyses. The results confirmed well-dispersed Pt NPs and strong metal–support interaction. Catalytic activity was evaluated under varying composition, catalyst dose, temperature, and UV light. Among all catalysts evaluated, Pt NPs/5CuONb30 showed the best performance, with a hydrogen generation rate (HGR) of 6336 mL min–1 g–1 and an activation energy of 75.9 kJ mol–1. The catalyst showed good stability and recyclability, retaining ∼90% of its activity after six cycles. The kinetic isotope effect (KIE) was found to be 5.60, indicating that the breaking of the O–H bond in water is the rate-determining step in the reaction. Visible light enhanced hydrogen generation, indicating photocatalytic potential. These results demonstrate that niobium-based composites are promising supports for noble metal catalysts and can contribute to the development of sustainable and efficient systems for hydrogen production.