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제124회 대한화학회 학술발표회, 총회 및 기기전시회 안내 Enhanced Catalytic Activity of SOx-Incorporated Graphene for Hydrogen Evolution Reaction

2019년 8월 29일 14시 37분 03초
ELEC.P-442 이곳을 클릭하시면 발표코드에 대한 설명을 보실 수 있습니다.
10월 17일 (목요일) 11:00~12:30
저자 및
Chiho Lee, Sang Uck Lee1,*
Department of Bionano Technology, Hanyang University, Korea
1Department of Chemical and Molecular Engineering, Hanyang University, Korea
The intrinsic catalytic activity of carbon-based nanostructures can be improved by incorporating heteroatom defects that result from geometric and electronic effects. Therefore, sulfur defects are used to enhance the catalytic activity of carbon-based nanostructures in hydrogen evolution reaction (HER). This is accomplished by increasing the hydrogen adsorption ability due to the large size of sulfur atoms, which induces structural deformation by increasing the sp3 character of graphene carbons. However, the effect of sulfur oxidation on HER catalytic activity has not yet been discussed, even though sulfur can easily be oxidized to sulfur oxide (SOx) in acidic environments, which may decrease the metallicity of graphene by opening the bandgap. Herein, we systematically investigate the HER catalytic activity of SOx-incorporated graphene, SOx@G (x=2, 3 or 4), based on the electronic, thermodynamic and kinetic viewpoints. Our results reveal that SO3@G on the basal plane has superior HER catalytic activity among the SOx@G materials due to its metallic nature and ability to stabilize adsorbed hydrogen (H*) that results from electrostatic interactions between SO3 and H* in an intermediate state. As a thermodynamic descriptor of the HER catalytic activity, the hydrogen binding Gibbs free energy (∆GVolmer) is calculated as -0.04 eV for SO3@G in the Volmer step, which is the most improved value. In particular, this value is close to zero, making SO3@G the ideal catalyst compared to S@G. In addition, the activation energies at both the Volmer and Tafel steps (∆EVolmer and ∆ETafel, respectively) of SO3@G show the lowest energy barriers among SOx@G, taking values of 0.005 eV and 0.14 eV, respectively. Thus, these values can be used as kinetic descriptors that are close to that of conventional Pt catalysts.