Synergetic Optimization via Composition-Dependent Nanostructuring in Co-Mo-S Electrocatalysts for Efficient Hydrogen Evolution in Alkaline Solution
Synergetic Optimization via Composition-Dependent Nanostructuring in Co-Mo-S Electrocatalysts for Efficient Hydrogen Evolution in Alkaline Solution
复制标题
通过 Co-Mo-S 电催化剂中成分依赖性纳米结构的协同优化，实现碱性溶液中高效析氢
DOI：
10.20964/2018.04.31
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发表时间：
2018
影响因子：
1.5
通讯作者：
Mao Baodong
中科院分区：
文献类型：
--
作者：
Wang Bo;Liu Yanhong;Hao Jinhui;Zhong Junbo;Yu Furong;Zhang Kewei;Shen Hao;Mao Baodong
近年来，地球上丰富的金属硫化物通过电催化水分解制氢引起了广泛关注。然而，大多数工作仅限于酸性条件，而碱性条件下的析氢反应（HER）却很少被讨论。在这里，我们提出了一种在碳布上生长Co-Mo-S催化剂的有效策略，通过将钴与L-半胱氨酸和磷钼酸可控地掺入MoS 2 中，以实现CoS 2 和MoS 2 的协同相互作用。优化后的Co-Mo-S催化剂(Co:Mo=1:2)表现出显着提高的HER活性，在10 mA cm -2 的电流密度下过电势为92 mV，塔菲尔斜率为82 mV dec -1 。通过一系列表征研究了活性增强的根源，其中金属CoS 2 固有的快速HER动力学和MoS 2 的高活性表面积的协同效应起着至关重要的作用。当钴含量适量时，Co-Mo-S催化剂在碳布上表现出相对均匀的分布，以确保较大的表面积，而过量的钴会导致低活性表面积形成低HER活性的大CoS 2 颗粒。进一步的电化学测量表明，CoS 2 较大的交换电流密度和MoS 2 的高电化学双层电容（与活性表面积成正比）的结合共同促进了Co-Mo-S催化剂的HER活性增强。 Co-Mo-S/CC 催化剂在碱性溶液中也表现出强大的稳定性。我们的工作通过协同优化固有的析氢反应动力学和电化学活性表面积，为碱性条件下高效三元过渡金属硫化物析氢催化剂的设计提供了更深刻的理解和有趣的观点。
Earth-abundant metal sulfides attracts large attention in recent years for hydrogen production via electrocatalytic water splitting. However, most works have been limited to the acidic condition, whereas the hydrogen evolution reaction (HER) in alkaline condition has rarely been discussed. Here we present an effective strategy for the growing of Co-Mo-S catalysts on carbon cloth via the controllable incorporation of cobalt into MoS 2 with L-cysteine and phosphomolybdic acid to achieve the synergistic interaction of CoS 2 and MoS 2 . The optimized Co-Mo-S catalysts (Co:Mo=1:2) showed a largely improved HER activity with an overpotential of 92 mV at current density of 10 mA cm -2 and Tafel slope of 82 mV dec -1 . The origin of the activity enhancement was investigated through a series of characterizations, where the synergetic effect of the intrinsic fast HER kinetics of metallic CoS 2 and the high active surface area of MoS 2 plays a crucial role. With appropriate amount of cobalt, the Co-Mo-S catalysts show a relatively uniform distribution on the carbon cloth to ensure the large surface area, whereas excessive cobalt results in the formation of the large CoS 2 particles with low HER activity from the low active surface area. Further electrochemical measurements demonstrated that the combination of larger exchange current density of CoS 2 and the high electrochemical double–layer capacitance (proportional to the active surface area) of MoS 2 together contributed to the HER activity enhancement of the Co-Mo-S catalysts. The Co-Mo-S/CC catalysts also show robust stability in alkaline solution. Our work provides a more profound understanding and an interesting view for the design of efficient ternary transition metal sulfide HER catalysts in alkaline condition by synergetic optimization of the intrinsic HER kinetics and the electrochemical active surface area.