Fuel Cell Research Center, Korea Institute of Science and Technology (KIST), 02792, Seoul, Republic of Korea.
Applied Materials Examination Division, Korean Intellectual Property Office (KIPO), 35208, Daejeon, Republic of Korea.
Sci Rep. 2017 Aug 15;7(1):8236. doi: 10.1038/s41598-017-08296-0.
Electrochemical water splitting is one of the most promising systems by which to store energy produced from sustainable sources, such as solar and wind energy. Designing robust and stable electrocatalysts is urgently needed because of the relatively sluggish kinetics of the anodic reaction, i.e. the oxygen evolution reaction (OER). In this study, we investigate the anomalous in situ activation behaviour of carbon-supported NiP nanoparticles (NiP/C) during OER catalysis in alkaline media. The activated NiP/C shows an exceptionally high activity and stability under OER conditions in which the overpotential needed to achieve 10 mA cm was reduced from approximately 350 mV to approximately 300 mV after 8,000 cyclic voltammetric scans. In situ and ex situ characterizations indicate that the activity enhancement of NiP catalysts is due to a favourable phase transformation of the Ni centre to β-NiOOH, including increases in the active area induced by structural deformation under the OER conditions. These findings provide new insights towards designing transition metal/phosphide-based materials for an efficient water splitting catalyst.
电化学水分解是储存来自可持续能源（如太阳能和风能）的能量的最有前途的系统之一。由于阳极反应（即析氧反应，OER）的动力学相对较慢，因此迫切需要设计稳健且稳定的电催化剂。在这项研究中，我们研究了在碱性介质中 OER 催化过程中负载在碳上的 NiP 纳米颗粒（NiP/C）的异常原位活化行为。在 OER 条件下，经过 8000 次循环伏安扫描后，激活的 NiP/C 表现出异常高的活性和稳定性，达到 10 mA cm 所需的过电势从约 350 mV 降低至约 300 mV。原位和非原位表征表明，NiP 催化剂活性的增强归因于 Ni 中心向β-NiOOH 的有利相转变，包括在 OER 条件下结构变形引起的活性面积增加。这些发现为设计用于高效水分解催化剂的过渡金属/磷化物基材料提供了新的见解。
