title: Cage-Confinement Pyrolysis Route to Ultrasmall Tungsten Carbide Nanoparticles for Efficient Electrocatalytic Hydrogen Evolution.
abstract: The size-controlled synthesis of ultrasmall metal-based catalysts is of vital importance for chemical conversion technologies. Here, a cage-confinement pyrolysis strategy is presented for the synthesis of ultrasmall tungsten carbide nanoclusters/nanoparticles. An RHO type zeolitic metal azolate framework MAF-6, possessing large nanocages and small apertures, is selected to confine the metal source W(CO)6. High temperature pyrolysis gives tungsten carbide nanoclusters/nanoparticles with sizes ca. 2 nm, which can serve as an excellent electrocatalyst for the hydrogen evolution reaction. In 0.5 M H2SO4, it exhibits very low overpotential of 51 mV at 10 mA cm-2and Tafel slope of 49 mV per decade, as well as the highest exchange current density of 2.4 mA cm-2among all tungsten/molybdenum-based catalysts. Moreover, it also shows excellent stability and antiaggregation behavior after long-term electrolytic process.
authors.affiliation: MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry, Sun Yat-Sen University , Guangzhou 510275, China.
authors.forename: Yan-Tong
authors.initials: YT
authors.lastname: Xu
authors.affiliation: Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education, Key Laboratory of High Performance Polymer-Based Composites of Guangdong Province, School of Chemistry, Sun Yat-Sen University , Guangzhou 510275, China.
authors.forename: Xiaofen
authors.initials: X
authors.lastname: Xiao
authors.affiliation: MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry, Sun Yat-Sen University , Guangzhou 510275, China.
authors.forename: Zi-Ming
authors.initials: ZM
authors.lastname: Ye
authors.affiliation: CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology , Beijing 100190, China.
authors.forename: Shenlong
authors.initials: S
authors.lastname: Zhao
authors.affiliation: Department of Chemistry, Tsinghua University , Beijing 100084, China.
authors.forename: Rongan
authors.initials: R
authors.lastname: Shen
authors.affiliation: MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry, Sun Yat-Sen University , Guangzhou 510275, China.
authors.forename: Chun-Ting
authors.initials: CT
authors.lastname: He
authors.affiliation: MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry, Sun Yat-Sen University , Guangzhou 510275, China.
authors.forename: Jie-Peng
authors.identifier: 0000-0002-2614-2774
authors.initials: JP
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, Tsinghua University , Beijing 100084, China.
authors.forename: Yadong
authors.identifier: 0000-0003-1544-1127
authors.initials: Y
authors.lastname: Li
authors.affiliation: MOE Key Laboratory of Bioinorganic and Synthetic Chemistry, School of Chemistry, Sun Yat-Sen University , Guangzhou 510275, China.
authors.forename: Xiao-Ming
authors.identifier: 0000-0002-3353-7918
authors.initials: XM
authors.lastname: Chen