GREEN NANOMATERIAL SYNTHESIS VIA RF SPUTTERING IN LIQUIDS AND ONTO POWDERS FOR SCALABLE, CRM-FREE CATALYSTS FOR WATER ELECTROLYSIS

We presented a dry and green synthesis approach using RF magnetron sputtering, a physical vapor deposition (PVD) technique, to fabricate nanofluids (nanoparticles suspended in liquids) and nanohybrids (catalyst-coated powders) as catalysts for water electrolysis applications. This solvent-free method eliminates hazardous chemicals and complex multi-step procedures, enabling sustainable and scalable production of ultrapure catalysts. For nanohybrids, copper-coated multi-walled carbon nanotubes (Cu/CNTs) and nickel-coated titania nanopowders (Ni/TiO2) were synthesized via RF magnetron sputtering combined with a vibrating deposition stage, which ensured uniform nanoparticle coating.1 For nanofluids, ultrapure nanoparticles (gold, copper, nickel, platinum) were obtained by RF sputtering directly into a liquid medium, preserving their native nanoscale morphology.2 These nanoparticles were then seamlessly transferred onto functional substrates such as Nafion membranes and graphene, forming uniform catalyst-coated membranes (CCM) and nanohybrids with ultra-low precious metal loading at the nanogram scale. Comprehensive characterization using SEM-EDX, XPS, XRD, AFM, and TEM confirmed nanoparticle integrity and dispersion. Electrochemical tests demonstrated an excellent hydrogen evolution reaction (HER) performance, comparable to commercial Pt-based materials. Therefore, this process addresses key challenges in PEM electrolyzer technology by lowering material costs, and offering a green, scalable, and industrially viable fabrication route.