Water-based plasma forges novel alloy to turn CO₂ into useful chemicals

Chinese researchers at Northeast Normal University have developed a novel water-based plasma technique to synthesize stable high-entropy alloy (HEA) nanoparticles directly in solution. These nanoparticles, composed of five metals (Fe, Co, Ni, Cr, Mn) in near-equal ratios, overcome traditional challenges in nanoscale alloy synthesis by forming a self-protecting oxidized shell that enhances stability and photothermal performance. The plasma process involves generating plasma between alloy rods submerged in water with oxide supports (e.g., TiO₂), which melts and rapidly cools alloy droplets to prevent metal separation, resulting in nearly spherical 200 nm particles anchored to the support. This method is versatile and can produce other HEA formulations. The HEA nanoparticles exhibit a metallic core with an oxidized shell rich in chromium and manganese, which stabilizes the particles during catalytic reactions. When supported on TiO₂, these catalysts efficiently convert CO₂ and hydrogen into carbon monoxide under visible and infrared light, achieving reaction rates significantly higher than