A Three-Dimensional Nickel–Chromium Layered Double Hydroxide Micro/Nanosheet Array as an Efficient and Stable Bifunctional Electrocatalyst for Overall Water Splitting
A Three-Dimensional Nickel–Chromium Layered Double Hydroxide Micro/Nanosheet Array as an Efficient and Stable Bifunctional Electrocatalyst for Overall Water Splitting
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三维镍铬层状双氢氧化物微/纳米片阵列作为高效稳定的全水分解双功能电催化剂
DOI：
10.1039/c8nr05974h
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发表时间：
2018
期刊：
影响因子：
6.7
通讯作者：
Yan Dongpeng
中科院分区：
文献类型：
--
作者：
Ye Wen;Fang Xiaoyu;Chen Xuebo;Yan Dongpeng
开发双功能、稳定的非贵金属电催化剂用于高性能的析氢反应（HER）和析氧反应（OER）对可再生能源具有重要意义和挑战。在此，第一次，镍-铬层状双氢氧化物（NiCr-LDH）纳米片阵列被开发为双功能电催化剂对整体水裂解。通过调节不同Ni/Cr比的LDH，优化的Ni 2Cr 1-LDH表现出优异的HER活性，在100 mA cm−2下的超电位为138 mV，与所有报道的Ni基LDH（NiFe-LDH，NiCo-LDH，NiMn-LDH，NiTi-LDH，NiV-LDH等）相比，甚至优于Pt/C催化剂。Ni 2Cr 1-LDH在100 mA cm−2下的OER过电位为319 mV，在1.55 V（相对于RHE）下30小时的耐久性也非常出色。值得注意的是，具有Ni 2Cr 1-LDH双功能电催化剂作为阳极和阴极的双电极电解槽可以在10 mA cm-2下仅1.55 V的电池电压下工作至少30小时。实验和密度泛函理论计算都表明，LDH层中的Cr ~（3+）离子作为电荷转移位点，有效地提高了LDH的电化学活性。因此，本工作提供了一种新的NiCr-LDH体系作为双功能水裂解电催化剂的更有效的金属氢氧化物。
The development of bifunctional and stable non-noble metal electrocatalysts for the high-performance hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is very important and challenging for renewable energy. Herein, for the first time, a nickel–chromium layered double hydroxide (NiCr-LDH) nanosheet array was developed as a bifunctional electrocatalyst towards overall water splitting. By tuning different Ni/Cr ratios of LDHs, the optimized Ni2Cr1-LDH shows extraordinary HER activity with an ultralow overpotential of 138 mV at 100 mA cm−2, compared with all of the reported Ni-based LDHs (NiFe-LDH, NiCo-LDH, NiMn-LDH, NiTi-LDH, NiV-LDH etc.) and even outperforming Pt/C catalysts. The small overpotential of 319 mV at 100 mA cm−2 for the OER and outstanding durability at 1.55 V (vs. RHE) for 30 hours can also be achieved for Ni2Cr1-LDH. Notably, a two-electrode electrolyzer with a Ni2Cr1-LDH bifunctional electrocatalyst as both the anode and the cathode can work for at least 30 hours with a cell voltage of merely 1.55 V at 10 mA cm−2. Both experimental and density functional theoretical calculations show that the Cr3+ ions within the LDH layer serve as charge transfer sites and thus effectively boost the intrinsic electrochemical activity. Therefore, this work provides a new NiCr-LDH system as a more efficient metal hydroxide for bifunctional water splitting electrocatalyst.