In Situ Spatially Coherent Identification of Phosphide-Based Catalysts: Crystallographic Latching for Highly Efficient Overall Water Electrolysis
In Situ Spatially Coherent Identification of Phosphide-Based Catalysts: Crystallographic Latching for Highly Efficient Overall Water Electrolysis
复制标题
DOI：
10.1021/acsenergylett.9b02075
复制
发表时间：
2019-12-01
影响因子：
22
通讯作者：
Chen, Hao Ming
中科院分区：
文献类型：
--
作者：
Hung, Sung-Fu;Zhu, Yanping;Chen, Hao Ming
磷化物基电催化剂在碱性溶液中表现出高活性，可用于水的全面电解。但是，它们在催化过程中的真实的相尚未得到全面的鉴定，导致在材料识别和理论模拟方面的不当推进。在这项工作中，原位空间相干透射X射线衍射和X射线吸收光谱被开发来探测Fe掺杂磷化钴，呈现出上级催化活性和反应动力学的整体水电解相比，原始磷化钴。结果表明，Fe掺杂剂锁定了磷化物的晶位，稳定了磷化物相，磷化物相是析氢反应的活性物种，而原始磷化钴转化为氢氧化物，阻碍了活性物质的形成。此外，Fe掺杂磷化钴在析氧反应中迅速转化为活性位受限的羟基氧化物，具有优异的催化性能。在电催化过程中发现的真实材料表明，适当的催化机制与相变和结晶转化率相关。
Phosphide-based electrocatalysts exhibit high activities in alkaline solution toward overall water electrolysis. However, their real phases during catalysis have not been comprehensively identified, leading to improper advancement in material recognition and theoretical simulation. In this work, in situ spatially coherent transmitted X-ray diffraction and X-ray absorption spectroscopy were developed to probe Fe-doped cobalt phosphides, presenting superior catalytic activity and reaction kinetics for overall water electrolysis compared to pristine cobalt phosphides. The results showed that Fe dopants latched the crystallographic sites and stabilized the phosphide phase, which are the active species for hydrogen evolution reaction, while pristine cobalt phosphide transformed into hydroxides that impede the formation of active substances. Besides, Fe-doped cobalt phosphides swiftly converted into active-site confined oxyhydroxide for oxygen evolution reaction, achieving superb overall catalytic performance. The genuine materials unveiled during the electrocatalysis suggest that the appropriate catalytic mechanism correlates with the phase transition and crystalline transformation rate.