Hollow Cobalt-Based Bimetallic Sulfide Polyhedra for Efficient All-pH-Value Electrochemical and Photocatalytic Hydrogen Evolution

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• 作者：Zhen-Feng Huang ; Jiajia Song ; Ke Li ; Muhammad Tahir ; Yu-Tong Wang ; Lun Pan ; Li Wang ; Xiangwen Zhang ; Ji-Jun Zou
• 刊名：Journal of the American Chemical Society
• 出版年：2016
• 出版时间：February 3, 2016
• 年：2016
• 卷：138
• 期：4
• 页码：1359-1365
• 全文大小：614K
• ISSN：1520-5126

文摘

The development of highly active, universal, and stable inexpensive electrocatalysts/cocatalysts for hydrogen evolution reaction (HER) by morphology and structure modulations remains a great challenge. Herein, a simple self-template strategy was developed to synthesize hollow Co-based bimetallic sulfide (M_xCo_3–xS₄, M = Zn, Ni, and Cu) polyhedra with superior HER activity and stability. Homogenous bimetallic metal–organic frameworks are transformed to hollow bimetallic sulfides by solvothermal sulfidation and thermal annealing. Electrochemical measurements and density functional theory computations show that the combination of hollow structure and homoincorporation of a second metal significantly enhances the HER activity of Co₃S₄. Specifically, the homogeneous doping in Co₃S₄ lattice optimizes the Gibbs free energy for H* adsorption and improves the electrical conductivity. Impressively, hollow Zn_0.30Co_2.70S₄ exhibits electrocatalytic HER activity better than most of the reported nobel-metal-free electrocatalysts over a wide pH range, with overpotentials of 80, 90, and 85 mV at 10 mA cm^–2 and 129, 144, and 136 mV at 100 mA cm^–2 in 0.5 M H₂SO₄, 0.1 M phosphate buffer, and 1 M KOH, respectively. It also exhibits photocatalytic HER activity comparable to that of Pt cocatalyst when working with organic photosensitizer (Eosin Y) or semiconductors (TiO₂ and C₃N₄). Furthermore, this catalyst shows excellent stability in the electrochemical and photocatalytic reactions. The strategy developed here, i.e., homogeneous doping and self-templated hollow structure, provides a way to synthesize transition metal sulfides for catalysis and energy conversion.