State Key Laboratory of Nuclear Resources and Environment, School of Chemistry, Biology and Materials Science , East China University of Technology , Nanchang 330013 , P. R. China.
Inorg Chem. 2019 Mar 4;58(5):3247-3255. doi: 10.1021/acs.inorgchem.8b03327. Epub 2019 Feb 12.
Bifunctional electrocatalysts based on transition-metal phosphides are appealing for overall water splitting owing to their excellent electrical conductivity, low cost, and high stability. However, these specials are often restricted by some serious drawbacks such as its relatively poor activity for oxygen evolution reaction (OER) and its manufacture, which usually requires one to add additional large numbers of P sources and, consequently, inevitably leads to the release of flammable and detrimental PH. Herein, we show an effective avenue to overcome these issues. For the first time, the in situ topological transformation of PO-intercalated NiFeAl-layered double hydroxide nanosheet arrays upon calcination under a H atmosphere is developed to fabricate supported nickel phosphide without any additional P source. The resulting phase affords unique NiP@NiFeAlO core-shell nanosheet arrays, which exhibit an excellent performance for OER and hydrogen evolution reaction in 1.0 M KOH, with low overpotentials of 210 and 105 mV at 10 mA cm, respectively. Impressively, it can also serve as both a cathode and an anode to drive water splitting in alkaline media, giving 10 and 100 mA cm at cell voltages of only 1.52 and 1.62 V, respectively. This value is better than the commercial criterion of the Pt/C//IrO counterpart and also ranks at the top level in all established bifunctional electrocatalysts. The outstanding performance of NiP@NiFeAlO is mainly attributed to the synergistic effect from a highly dispersed NiP core and a thin NiFeAlO shell, as well as the efficient mass transport of a hierarchical nanoarray framework.
基于过渡金属磷化物的双功能电催化剂由于其优异的导电性、低成本和高稳定性而在全水解中很有吸引力。然而，这些磷化物通常受到一些严重缺点的限制，例如其对析氧反应 (OER) 的活性相对较差，以及其制造通常需要添加额外的大量磷源，因此不可避免地会导致易燃和有害的 PH 的释放。在此，我们展示了一种克服这些问题的有效途径。首次在 H 气氛下煅烧时，通过原位拓扑转化方法制备了 PO 插层 NiFeAl 层状双氢氧化物纳米片阵列负载的镍磷化物，无需添加任何额外的磷源。所得相提供了独特的 NiP@NiFeAlO 核壳纳米片阵列，在 1.0 M KOH 中对 OER 和析氢反应表现出优异的性能，在 10 mA cm 时的过电位分别为 210 和 105 mV。令人印象深刻的是，它还可以作为阴极和阳极在碱性介质中驱动水分解，在仅 1.52 和 1.62 V 的电池电压下分别产生 10 和 100 mA cm。该值优于商业 Pt/C//IrO 标准，在所有已建立的双功能电催化剂中也处于最高水平。NiP@NiFeAlO 的优异性能主要归因于高度分散的 NiP 核和薄的 NiFeAlO 壳的协同效应，以及分层纳米阵列结构的高效质量传输。
