Academy of Scientific and Innovative Research (AcSIR) , Karaikudi 630 003, Tamil Nadu India.
ACS Appl Mater Interfaces. 2017 Apr 19;9(15):13132-13141. doi: 10.1021/acsami.6b16685. Epub 2017 Apr 4.
Catalysts for the oxygen evolution reaction (OER) play an important role in the conversion of solar energy to fuel of earth-abundant water into H and O through splitting/electrolysis. Heterogeneous electrocatalysts for hydrogen and oxygen evolution reactions (HER and OER) exhibit catalytic activity that depends on the electronic properties, oxidation states, and local surface structure. Spinel ferrites (MFeO; M = Ni and Co) based materials have been attractive for the catalytic water oxidation due to their well-known stability in alkaline medium, easy synthesis, existence of metal cations with various oxidation states, low cost, and tunable properties by the desired metal substitution. To understand the better catalytic activity of MFeO in detail the role of Ni and Co was studied through MNiFeO (M = Co; 0 < x < 1), which was prepared by the sol-gel method. The results showed that bare NiFeO has better catalytic activity (η = 381 mV at 10 mA cm and Tafel slope of 46.4 mV dec) compared to Co-containing MNiFeO (η = 450-470 mV at 10 mA cm and Tafel slope of 50-73 mV dec) in alkaline medium, and the substitution of Co is found to suppress the catalytic activity of NiFeO. The degradation of catalytic activity with an increase in Co content was accounted for in further detailed investigations.
用于氧气析出反应 (OER) 的催化剂在通过分解/电解将太阳能转化为丰富地球资源的水的 H 和 O 燃料方面发挥着重要作用。用于析氢反应 (HER) 和析氧反应 (OER) 的多相电催化剂表现出依赖于电子特性、氧化态和局部表面结构的催化活性。基于尖晶石铁氧体 (MFeO；M = Ni 和 Co) 的材料由于在碱性介质中具有良好的稳定性、易于合成、存在具有各种氧化态的金属阳离子、低成本以及通过所需的金属取代来调整性质而受到用于催化水氧化的吸引力。为了详细了解 MFeO 的更好的催化活性，通过溶胶-凝胶法制备了 MNiFeO (M = Co；0 < x < 1) 来研究 Ni 和 Co 的作用。结果表明，与含有 Co 的 MNiFeO (在碱性介质中 10 mA cm 时的 η = 450-470 mV 和 Tafel 斜率为 50-73 mV dec) 相比，裸 NiFeO 具有更好的催化活性 (η = 381 mV，在 10 mA cm 时的 Tafel 斜率为 46.4 mV dec)，并且 Co 的取代被发现抑制了 NiFeO 的催化活性。进一步的详细研究说明了随着 Co 含量的增加，催化活性的降解。
