A Direct Synthesis of Platinum/Nickel Co-catalysts on Titanium Dioxide Nanotube Surface from Hydrometallurgical-type Process Streams

Solutions that simulate hydrometallurgical base metal process streams with high nickel (Ni) and minor platinum (Pt) concentrations were used to create Pt/Ni nanoparticles on TiO₂ nanotube surfaces. For this, electrochemical deposition – redox replacement (EDRR) was used that also allowed to control the nanoparticle size, density and Pt/Ni content of the deposited nanoparticles. The Pt/Ni nanoparticle decorated titanium dioxide nanotubes (TiO₂ nanotubes) become strongly activated for photocatalytic hydrogen (H₂) evolution. Moreover, EDRR facilitates nanoparticle formation without the need for any additional chemicals and is more effective than electrodeposition alone. Actually, a 10,000-time enrichment level of Pt took place on the TiO₂ surface when compared to Pt content in the solution with the EDRR method. The results show that hydrometallurgical streams offer great potential as an alternative raw material source for industrial catalyst production when coupled with redox replacement electrochemistry.