Tuning Electronic Structure of NiFe Layered Double Hydroxides with Vanadium Doping toward High Efficient Electrocatalytic Water Oxidation
Tuning Electronic Structure of NiFe Layered Double Hydroxides with Vanadium Doping toward High Efficient Electrocatalytic Water Oxidation
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钒掺杂调整 NiFe 层状双氢氧化物的电子结构以实现高效电催化水氧化
DOI：
10.1002/aenm.201703341
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发表时间：
2018-05-25
影响因子：
27.8
通讯作者：
Sun, Xiaoming
中科院分区：
文献类型：
--
作者：
Li, Pengsong;Duan, Xinxuan;Sun, Xiaoming
二元NiFe层状双氢氧化物（LDH）作为基准的非贵金属电催化剂用于析氧反应，然而，它仍然需要相对高的过电位来实现阈值电流密度。在本文中，催化剂的电子结构通过将钒离子掺杂到NiFe LDHs层压体中形成三元NiFeV LDHs来调节，以降低起始电位，实现前所未有的水氧化的高效电催化。在1 M KOH溶液中，仅需1.42 V（相对于可逆氢电极（RHE），过电位约为195 mV）即可获得20 mA cm（-2）的催化电流密度和42 mV dec（-1）的小Tafel斜率，这表明NiFe基催化剂是迄今为止报道的最佳催化剂。电化学分析和密度泛函理论+U模拟表明，NiFeV LDHs的高催化活性主要归因于钒的掺杂改变了LDHs的电子结构，使LDHs的禁带宽度变窄，从而提高了LDHs的电导率，促进了电子转移，增加了LDHs的活性中心。
Binary NiFe layer double hydroxide (LDH) serves as a benchmark non-noble metal electrocatalyst for the oxygen evolution reaction, however, it still needs a relatively high overpotential to achieve the threshold current density. Herein the catalyst's electronic structure is tuned by doping vanadium ions into the NiFe LDHs laminate forming ternary NiFeV LDHs to reduce the onset potential, achieving unprecedentedly efficient electrocatalysis for water oxidation. Only 1.42 V (vs reversible hydrogen electrode (RHE), approximate to 195 mV overpotential) is required to achieve catalytic current density of 20 mA cm(-2) with a small Tafel slope of 42 mV dec(-1) in 1 M KOH solution, which manifests the best of NiFe-based catalysts reported till now. Electrochemical analysis and density functional theory +U simulation indicate that the high catalytic activity of NiFeV LDHs mainly attributes to the vanadium doping which can modify the electronic structure and narrow the bandgap thereby bring enhanced conductivity, facile electron transfer, and abundant active sites.