Designing Surface Wettability for Enhanced Interfacial Phenomena

Modified wettability allows significant performance enhancements in materials and devices without changing their bulk composition, making it an attractive and cost-effective strategy for optimizing device efficiency. This work aims to modify the wettability of carbon materials, ranging from hydrophilic to superhydrophobic states, to enhance the performance of catalysts for Oxygen Reduction Reaction (ORR). The studied carbons were Vulcan XC72 (Cabot Corporation), Acetylene Black Y70 and Acetylene Black YS (Orion Engineered Carbons). The properties of the powders were investigated through Dynamic Light Scattering (DLS) and Brunauer-Emmett-Teller analysis (BET). The wettability behaviour of the samples was studied on tablets, through the application and improvement of a literature kinetic model, and on films with different solvents. The influence of Nafion in the deposition was also studied. Cyclic Voltammetry was used to study ORR using Rotating Ring Disk Electrode loaded with carbon. The electrochemical tests also included Double Layer Capacitance determination, H2O2 unwanted production and kinetic study with the application of Levich equation. The results highlighted that improved performances can be obtained with hydrophobic materials. As final step, the properties of bare Vulcan XC72 and Pt/Vulcan XC72 at different wettability were evaluated with Zeta-potential, DLS and electrochemical tests.