Nitrogen Plasma-treated Continuous Monolayer MoS<sub>2</sub> Film for Improving Hydrogen Evolution Reaction
ORAL
Abstract
Large density of active sites and near zero Gibbs free energy renders two-dimensional (2D) MoS2 is ideal platforms to investigate low-cost hydrogen evolution reaction (HER) compared to the noble metal in terms of cost. Recently reported metal-organic chemical vapor deposition (MOCVD) is a good synthetic method for continuous and conformal monolayer transition metal dichacogenide. [1,2] However, the intrinsic defects and the grain boundaries in MOCVD-grown TMDC are still limited to provide enough active sites for high efficient HER. In this work, we employed nitrogen plasma to enhance the active sites on the continuous MoS2 surface for further improving the ratio of the edge to basal sites. Initially, the optical properties were investigated by using in-situ PL and Raman spectroscopy. Furthermore, the surface morphology was examined by using FE-SEM and in-situ AFM. The HER results shows that the sample treated for 20 minutes at 0.02 mA and 20 kV showed the best performance. The sample showed reduced onset overpotential of -0.25 mV compared to the as-grown MoS2 (-0.48 mV). [1] K. Kang, et al., Nature 520, 656 (2015). [2] E. Kim, et al., Nanoscale 10, 18920 (2018).
*This research was supported by the NRF of Korea (2009-0093818; 2014R1A4A1071686; 2017R1E1A1A01075350).
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Presenters
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Anh Duc Nguyen
- Department of Physics and Energy Harvest-Storage Research Center, University of Ulsan