121st General Meeting of the KCS

Type Poster Presentation
Area Electrochemistry
Room No. Event Hall
Time 4월 20일 (금요일) 11:00~12:30
Code ELEC.P-636
Subject Nanostructured rhenium-carbon composites as hydrogen-evolving catalysts effective over the entire pH range
Authors Minju Kim, Junheuk Park, Bartosz Grzybowski*
IBS Center for Soft and Living Matter / Department of Chemistry, Ulsan National Institute of Science and Technology, Korea
Abstract Hydrogen evolution reaction (HER) enables electrochemical water splitting and has been the focus of much recent research on sustainable and clean energy sources. Owing to minimal overpotential and fast kinetics, Pt-based catalysts have been most popular in HER, but they are expensive and have limited stability in alkaline media used in most industrial electrolyzers. Accordingly, other metals (e.g., Ru, Co, Mo, Ni, W, and Fe) and their chalcogenides, phosphides, and carbides have been explored as alternatives to Pt. Ominously, this list does not include Re, although the so-called Sabatier plot (a.k.a. volcano plot) suggests its usefulness as an efficient HER catalyst. Rhenium exhibits optimal binding energy for adsorption and desorption of protons as well as exchange current density for HER that is comparable to Pt.; it is also about an order of magnitude less expensive than platinum. On the other hand, the bulk-state metallic Re HER catalysts used to date have required high overpotentials (>200 ~ 300 mV at 10 mA/cm2). In addition, few reports investigated the HER performance in alkaline electrolytes. Here, we describe efficient HER catalysis on nanoparticle clusters in which Re is combined with electrical conductive carbon materials such as amorphous carbon (a-C) or multi-walled carbon nanotubes (MWNTs). These nanocomposites are not only characterized by low overpotentials and fast kinetics but also remain efficient in both acidic and basic media. Our results suggest that Re-based nanomaterials can become less expensive and sturdy (in terms of admissible pH range) alternatives to the currently used HER catalysts.
E-mail minju@unist.ac.kr