120th General Meeting of the KCS

Type Oral Presentation
Area Oral Presentation of Young Scholars in Electrochemistry
Room No. Room 201+202
Time THU 09:00-:
Code ELEC.O-1
Subject Electrocatalytic Hydrogen Production on Molecular-like Metal Nanoclusters
Authors woojun choi, Kyuju Kwak, Minseok Kim, Dongil Lee*
Department of Chemistry, Yonsei University, Korea
Abstract Hydrogen has received great attention with respect to its possibility for replacing fossil fuel as alternative energy sources. Hydrogen evolution reaction (HER) catalysts are usually divided into two categories such as metallic heterogeneous catalysts and synthetic molecular homogeneous catalysts. The latter usually mimicking neutral enzyme, hydrogenase, that is one of the most active HER catalyst due to its unique proton relaying process and thermodynamically neutral Gibbs free energy for binding between H+ and active site (∆GH = ~0 eV). Ultrasmall Au25 nanocluster that has both metallic and molecular-like characteristics exhibits distinctive electrochemical properties and unique catalytic activities. In this presentation, we report electronic structures and catalytic properties of Au25(SR)18 and bimetallic PtAu24(SR)18 nanoclusters (SR = thiolate). Electrocatalytic HER activities of nanoclusters were demonstrated by linear sweep voltammetry (LSV) and controlled potential electrolysis (CPE) was conducted for real gas detection. Calculated ∆GH by density functional theory (DFT) supported the intrinsic HER activities of nanoclusters. Au25 catalyzes hydrogen production with onsetpotential (Eonset) = -0.3 V vs. RHE and turnover frequency (TOF) for HER reached 8.8 s-1 at -0.6 V. PtAu24 showed promoted HER activity with very low Eonset (70 mV) that is comparable to that of hydrogenase (~100 mV) and high TOF (33.4 s-1 at -0.6 V). This would be ascribed that moderate ∆GH of PtAu24 (-0.059 eV) compare to Au25 that have too week binding energy with H+ (∆GH = 0.539 eV).
E-mail phungse@naver.com