122nd General Meeting of the KCS

Type Oral Presentation
Area Oral Presentation of Young Scholars in Electrochemistry
Room No. Room 320
Time THU 09:15-:
Code ELEC.O-2
Subject Atomically Controlled Bimetallic Nanoclusters as Electrocatalysts for Hydrogen Production
Authors Woojun Choi, Kyuju Kwak, Minseok Kim, Dongil Lee*
Department of Chemistry, Yonsei University, Korea
Abstract Hydrogen is widely considered as a clean and renewable energy carrier. Thus, identification of an efficient hydrogen evolution reaction (HER) electrocatalysts is one of the great challenging fields to replace the fossil fuel. Ligand protected Au nanoclusters exhibit distinctive electrochemical property and HER activity. The HER activity could be improved not only by doping of Pd or Pt to achieve thermoneutral binding step with H+ (∆GH = ~0 eV) but also by introducing proton rich ligand for fast proton relay from ligand to active site. In this presentation, we report electronic structures and catalytic properties of Au25(SR)18 and bimetallic MAu24(SR)18 (M = Pt or Pd) nanoclusters (SR = thiolate). The modified catalytic activities were demonstrated by linear sweep voltammetry and controlled potential electrolysis. HER turnover frequency (TOF) of hexanthiol (C6S) protected Au25(C6S)18 (8.8 s-1 at -0.6 V vs. RHE) increased by doping of Pd (13.0 s-1) and further enhanced by doping of Pt (PtAu24(C6S)18, 33.4 s-1). Calculated ∆GH by density functional theory supported the enhanced HER activities of Pd and Pt doped nanoclusters. The TOF of Pt-doped nanocluster could further increase by introducing carboxylate or sulfonate ligands reached to 100 s-1 at -0.6 V. Furthermore, Pt-doped nanoclusters catalyze hydrogen production from very low onset potential (Eonset = -0.07 V) due to matched reduction potential with proton (H+/H2) whereas Au25 showed mismatched reduction potential and higher Eonset (-0.20 V).
E-mail phungse@naver.com