The Role of Cr Doping in NiFe Oxide/(Oxy)Hydroxide Electrocatalysts for Oxygen Evolution
The Role of Cr Doping in NiFe Oxide/(Oxy)Hydroxide Electrocatalysts for Oxygen Evolution
复制标题
Cr 掺杂在 NiFe 氧化物/(氧)氢氧化物析氧电催化剂中的作用
DOI：
10.1016/j.electacta.2018.01.143
复制
发表时间：
2018
影响因子：
6.6
通讯作者：
Wang Hongzhi
中科院分区：
文献类型：
--
作者：
Xu Dongyu;Stevens Michaela Burke;Rui Yichuan;DeLuca Giovanni;Boettcher Shannon W.;Reichmanis Elsa;Li Yaogang;Zhang Qinghong;Wang Hongzhi
用于水氧化的高效和地球丰富的电催化剂对于可再生和可持续的能源转换技术至关重要。其中Ni（Fe）OxHy-Ni（Fe）在以往的研究中，Cr的加入对Ni（Fe）OxHy催化剂的催化活性有一定的促进作用，但其作用机理与Cr的存在有一定的矛盾。本文采用简单的热分解法合成了一系列用于OER的三元非晶态金属氧化物催化剂。我们发现，Ni0.6Fe0.3Cr0.1Ox在300 mV过电位下的转换频率为0.046 ± 0.004 s− 1，比0.1 M KOH介质中的类似Ni0.6Fe0.4Ox膜（0.035 ± 0.007 s−1）高出约31%。使用电化学伏安法和交流阻抗分析，我们表明，铬增加了电化学可用的活性位点的数量，作为成孔剂，但不影响固有的每金属原子的活性。我们发现，在电化学测试后，Cr立即开始浸出，并且在24小时稳定性测试后，Cr几乎完全耗尽。重要的是，沿着Cr含量的降低，催化剂活性进一步提高。虽然Cr本身可能不是改善的原因，但其溶解导致理想类型的孔和/或活性位点。我们进一步优化了高表面积和高质量负载的Ni0.6Fe0.3Cr0.1Oxon碳布电极的沉积，并在1 M KOH中在10 mA cm− 2时表现出低至251 mV的过电位。
Efficient and earth-abundant electrocatalysts for water oxidation are essential for renewable and sustainable energy conversion technologies. And Ni(Fe)OxHyespecially attractive as a state-of-the-art best candidate catalyst for efficient electrochemical oxygen evolution reaction (OER). In previous research, Cr has been reported could benefit the Ni(Fe)OxHycatalysts with conflicting mechanism. Here, a series of ternary (Ni, Fe and Cr) amorphous metal oxide catalysts for OER are synthesized via a simple thermal decomposition method. We show that Ni0.6Fe0.3Cr0.1Oxhas a turnover frequency of 0.046 ± 0.004 s−1at 300 mV overpotential which is ∼31% more active than an analogous Ni0.6Fe0.4Oxfilm, 0.035 ± 0.007 s−1, in 0.1 M KOH media. Using electrochemical voltammetry and AC impedance analysis, we demonstrate that Cr increases the number of electrochemically available active sites, as a pore forming agent, but does not affect the intrinsic per metal atom activity. We find that the Cr begins to leach immediately upon electrochemical testing, and the Cr is almost completely depleted after a 24 h stability test. Importantly, along with the decreased content of Cr, the catalyst activity is further promoted. Although the Cr itself may not be responsible for the improvement, its dissolution results in an ideal type of pore and/or active sites. We further optimize the deposition of high-surface-area and high-mass-loading Ni0.6Fe0.3Cr0.1Oxon carbon-cloth electrodes and demonstrate an overpotential as low as 251 mV at 10 mA cm−2in 1 M KOH.