Base metals doped ceria for bifunctional oxygen/hydrogen evolution reaction

Title : Base metals doped ceria for bifunctional oxygen/hydrogen evolution reaction

Abstract:

In order to find sustainable alternative energy due to the quick depletion of fossil fuels and environmental damage. One of promising methods for converting electricity generated from solar and wind renewable energy into chemical energy stored in hydrogen fuel is water splitting technique. The slow oxygen evolution reaction (OER) on the anode is the main issue from the overpotential. Actively bifunctional electrocatalysts are necessary to develop to lower the overpotential of oxygen and hydrogen evolution reaction (OER or HER). Conventionally effective electrocatalysts for water splitting are well-known as noble metals of Pt, Ru, Ir and their oxides. The low cost of CeO₂–based material with high valence change and high conductivity is one of good ceramic candidates for water splitting. The ceria doped by valence-changeable Fe and Ni base metals will be high catalytic activity and conductivity after treated in a reducing or oxygendeficient atmosphere. Those self-oxygen vacancies and electrons may generate in doped CeO₂ to provide the adsorption capacity of proton and oxygen species. The ceria doped with Fe, Ni, and Fe/Ni alloys prepared by semi-gelatinization (SG) methods mixed with Nafion-propanol solution then soaked with Ni-foam at 60°C for electrocatalysts coating. The ceria doped with Fe, Ni, and Fe/Ni alloys coated on Ni-form by elthyleneglycol slovothermal method at 170°C/12h, then annealed at 400°C/4h in Ar atmosphere. Both of doped ceria coated Ni-foams as working electrode were immersed in 1 M KOH electrolyte solution. The Pt sheet as counter electrode and Hg/HgO as reference electrode were to measure OER and HER. Preliminarily, 20 mol% Fe doped CeO₂ by SG coating and by solvothermal coating behaved lower OER overpotential of 0.25 V and 0.29 V in Nafion-propanol, respectively, than Ni-foam (10 [email protected]). HER of Ni-Foam (-100 [email protected]) was lower than 20 mol% Fe doped CeO₂ by SG coating and by solvothermal coating with 0.05V and 0.14V, respectively. Fe/Ni alloy formation and precipitated Fe on Ni foam may be the important OER and HER enhancement reason. Further electrocatalytic properties correlated to coating particles/grain size and nanostructures are undergoing to investigate the OER and HER efficiency.

Biography:

Professor Horng-Yi Chang has experienced as a department Manager in EMTAC Technology Corp. (Hsinchu Science Park) and a principal researcher in the Industrial Technology Research Institute (ITRI), Taiwan. Now, he is a professor of the Department of Marine Engineering, National Taiwan Ocean University, Taiwan. Professor Chang engaged in studying microwave sintering, core-shell structural materials and laser annealing process as well as nano-particles treatment. Recently, his research concentrates on energy materials about SOFC/SOEC, water splitting and luminescent energy conversion by use of chemical processes such as hydro/solvo-thermal, sol-gel, core-shell, precipitation and microwave techniques to synthesize, improve and enhance those materials’ properties for industrial applications.