Cage-Confinement Pyrolysis Route to Ultrasmall Tungsten Carbide Nanoparticles for Efficient Electrocatalytic Hydrogen Evolution.

Title Cage-Confinement Pyrolysis Route to Ultrasmall Tungsten Carbide Nanoparticles for Efficient Electrocatalytic Hydrogen Evolution.
Authors Y.T. Xu; X. Xiao; Z.M. Ye; S. Zhao; R. Shen; C.T. He; J.P. Zhang; Y. Li; X.M. Chen
Journal J Am Chem Soc
DOI 10.1021/jacs.7b00165
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(-2) and Tafel slope of 49 mV per decade, as well as the highest exchange current density of 2.4 mA cm(-2) among all tungsten/molybdenum-based catalysts. Moreover, it also shows excellent stability and antiaggregation behavior after long-term electrolytic process.

Citation Y.T. Xu; X. Xiao; Z.M. Ye; S. Zhao; R. Shen; C.T. He; J.P. Zhang; Y. Li; X.M. Chen.Cage-Confinement Pyrolysis Route to Ultrasmall Tungsten Carbide Nanoparticles for Efficient Electrocatalytic Hydrogen Evolution.. J Am Chem Soc. 2017. doi:10.1021/jacs.7b00165

Related Elements

Tungsten

See more Tungsten products. Tungsten (atomic symbol: W, atomic number: 74) is a Block D, Group 6, Period 6 element with an atomic weight of 183.84. The number of electrons in each of tungsten's shells is [2, 8, 18, 32, 12, 2] and its electron configuration is [Xe] 4f14 5d4 6s2. Tungsten Bohr ModelThe tungsten atom has a radius of 139 pm and a Van der Waals radius of 210 pm. Tungsten was discovered by Torbern Bergman in 1781 and first isolated by Juan José Elhuyar and Fausto Elhuyar in 1783. In its elemental form, tungsten has a grayish white, lustrous appearance. Elemental TungstenTungsten has the highest melting point of all the metallic elements and a density comparable to that or uranium or gold and about 1.7 times that of lead. Tungsten alloys are often used to make filaments and targets of x-ray tubes. It is found in the minerals scheelite (CaWO4) and wolframite [(Fe,Mn)WO4]. In reference to its density, Tungsten gets its name from the Swedish words tung and sten, meaning heavy stone.

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