2523
Cobalt-Based Oxygen Evolution Electrocatalysts Biotemplated on DOPA-Displaying Viruses

Tuesday, 15 May 2018
Ballroom 6ABC (Washington State Convention Center)
J. Rho (Department of Chemistry, Seoul National University) and T. D. Chung (Advanced Institutes of Convergence Technology, Department of Chemistry, Seoul National University)
The Oxygen evolution reaction (OER), which involves a more complex mechanism compared to hydrogen evolution reaction (HER), determines the whole cell efficiency for (photo)electrochemical water splitting. Lately, non-precious metal based oxygen evolution catalysts (OECs), such as transition metal oxides got attentions for OER under relatively benign conditions at low overpotentials. In this work, we report a filamentous bacteriophage fd displaying 3,4-dihydroxy-L-phenylanlanine (DOPA) onto the major coat protein and promoted the spontaneous deposition of cobalt oxide based oxygen evolution catalyst (Co-OEC) onto the phages. The virus successfully worked as a biotemplate to enable deposition of thin Co layer along wire-like bodies, and the catechol group of DOPA moiety stabilized Co2+ to accelerate Co-OEC deposition on virus and slightly enhanced OER activity. The Co-based catalysts adhered to DOPA-phages through electroless deposition (Co/DOPA-phages) showed cathodic shift of Co3+/2+ oxidation peak and this phenomenon could be explained from partial-charge transfer from cobalt to DOPA group, which is supported from X-ray photoelectron spectroscopy (XPS) that shows more distinct satellite peaks of Co2+ at ~786 eV compared to electrodeposited Co-OEC. It is widely accepted that partial charge transfer caused by dopant cations raise activity enhancement and change the OER mechanism. The pronounced OER activity under 10 mA cm-2 and long-term stability of Co/DOPA-phages suggest potential for further optimization via systematically ordered and denser array of catechol group for improved performance.