Os/Si nanocomposites as excellent hydrogen evolution electrocatalysts with thermodynamically more favorable hydrogen adsorption free energy than platinum. (September 2017)

• Record Type: Journal Article
• Authors: Cheng, Yafei; Fan, Xing; Liao, Fan; Lu, Shunkai; Li, Youyong; Liu, Liangbin; Li, Yanqing; Lin, Haiping; Shao, Mingwang; Lee, Shuit-Tong
• Is Part Of: Nano energy. Volume 39(2017:Sep.)
• Page Start: 284
• Page End: 290
• Publication Date: 2017-09
• Subjects: Hydrogen evolution reaction -- Os nanoparticles -- Si nanowires -- Electrocatalysts -- Adsorption free energy; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2017.07.009
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: The development of highly efficient electrocatalysts for hydrogen evolution reaction is a fundamental undertaking of the hydrogen economy. Herein, we investigated the electrocatalytic performance of M/Si (M = Os, Rh, Pt, Pd, Re, Ru, Au or Ag) nanocomposites for hydrogen evolution reaction. The results show that Os/Si nanocomposites exhibit the best catalytic efficiency with a negligible onset overpotential (−25 mV), a small Tafel slope of −24 mV dec −1 and remarkable long-term stability. Of most importance, at a current density of the typical industrial production (−1000 mA cm −2 ), the energy conversion efficiency of the Os/Si nanocomposite is 29.3% higher than that of the commercial 40 wt% Pt/C. The density functional calculations reveal that such outstanding catalytic activity of the Os/Si catalyst arises from the thermodynamically more favorable hydrogen adsorption free energy (Δ G H* = −0.03 eV) at the osmium/silicon interfaces than that on platinum (Δ G H* = −0.09 eV) or osmium (Δ G H* = −0.26 eV). Graphical abstract: Os/SiNW exhibits a thermodynamically favorable hydrogen adsorption free energy of −0.03 eV endowing its excellent electrocatalytic activity and stability for HER, which even surpasses 40 wt% Pt/C at overpotentials above −60 mV. Highlights: Os/Si has a thermodynamically favorable hydrogen adsorption free energy. Os/SiNW composites show a low Tafel slope of −24 mV dec −1 . The performance of Os/SiNW catalysts exceeds Pt/C at high overpotentials.