Liu Xiaojing, Cao Shuyi, Li Jingde, Wang Yanji, Xue Wei, Liu Guihua
School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin, 300130, China.
Small. 2023 Dec;19(50):e2304652. doi: 10.1002/smll.202304652. Epub 2023 Aug 25.
Active and stable electrocatalysts toward oxygen evolution reaction (OER) are essential for alkaline water splitting. Herein, an efficient and durable high-valence NiFe-based OER electrocatalyst is developed, featuring a protective CeO coating to prevent the corrosion of carbon substrates during oxidative OER operation, ensuring excellent catalyst stability. The incorporation of a CeO coating also leads to the formation of a Ce-doped NiFe sulfide catalyst. The Ce modulator enables the dynamic transformation of NiFe sulfide into highly active (oxy)hydroxide species with high-valence Ni sites and enhanced Ni─O covalency, thereby improving its OER catalytic activity. Accordingly, the prepared NiFeS /CeO /CC catalyst achieves enhanced OER activity with an overpotential of 260 mV at 100 mA cm in 1.0 m KOH. Moreover, the catalyst achieves 100 mA cm current density at an overpotential of 187 mV for the hydrogen evolution reaction. The anion exchange membrane water electrolyzer reached 500 mA cm at 1.73 V cell voltage with excellent stability for 500 h continuous operation. This study demonstrates a promising approach for the fabrication of robust water-splitting electrocatalysts.
对于碱性水分解而言，具有活性且稳定的析氧反应（OER）电催化剂至关重要。在此，开发了一种高效且耐用的高价镍铁基OER电催化剂，其具有保护性CeO涂层，可防止在氧化OER操作过程中碳基底被腐蚀，确保了优异的催化剂稳定性。CeO涂层的引入还导致形成了Ce掺杂的镍铁硫化物催化剂。Ce调节剂能够使镍铁硫化物动态转变为具有高价镍位点且Ni─O共价性增强的高活性（氧）氢氧化物物种，从而提高其OER催化活性。因此，制备的NiFeS/CeO/CC催化剂在1.0 m KOH中，在100 mA cm时过电位为260 mV，实现了增强的OER活性。此外，该催化剂在析氢反应中，在187 mV过电位下实现了100 mA cm的电流密度。阴离子交换膜水电解槽在1.73 V电池电压下达到了500 mA cm，具有出色的稳定性，可连续运行500 h。这项研究展示了一种制备坚固的水分解电催化剂的有前景的方法。
