One-Step Synthesis of Highly Active NiFe Electrocatalysts for the Oxygen Evolution Reaction

Abstract

Electrochemical water splitting is a key technology for the conversion of renewable energy into chemical resources such as hydrogen. However, the oxygen evolution reaction (OER), a half-reaction of water splitting, is so slow that various effective catalysts for the OER have been explored. In this study, we demonstrate a simple and direct process for the synthesis of OER-active NiFe catalysts over electrodes. A NiFe/C catalyst layer was formed on a glassy carbon electrode by simply dropping the catalyst ink containing only metal nitrates and carbon black. The catalyst layer exhibited higher OER performance than the state-of-the-art Ir/C catalyst. The presence of carbon black is essential to enhance the OER activity of NiFe because carbon black helps to disperse the NiFe active sites. Cyclic voltammetry indicated that Ni and Fe are adjacent to each other on the surface of carbon black, resulting in significantly higher activity of NiFe/C compared to those of Ni/C and Fe/C. The effects of the Ni/Fe ratio, amount of carbon black, and type of carbon black on the OER activity of NiFe/C were examined in detail. Furthermore, we discuss the factors that determine the OER performance of NiFe/C.

Alkali Containing Layered Metal Oxides as Catalysts for the Oxygen Evolution Reaction

“…Many studies have indeed shown that Fedoped nickel oxides are promising electrocatalysts for the OER. [70][71][72][73][74] Similar to Fe-doped nickel oxides, the effect of Fedoping in Li-layered metal oxides as electrocatalysts for the OER has been investigated. A series of Co-based oxides, LiCo 1-x M x O 2 (M = Ni, Fe and Mn) was also investigated by Lu et al using the same preparation methods as for LiCoO 2 and Li 0.5 CoO 2 .…”

“…The OER is an unwanted side reaction in NiO x alkaline batteries, and it has long been found that Fe impurities enhance such a process, [66–69] with this attracting significant attention to the effects of Fe‐doping in NiO x electrodes for OER electrocatalysis in alkaline media. Many studies have indeed shown that Fe‐doped nickel oxides are promising electrocatalysts for the OER [70–74] . Similar to Fe‐doped nickel oxides, the effect of Fe‐doping in Li‐layered metal oxides as electrocatalysts for the OER has been investigated.…”

Tunable Method for the Preparation of Layered Double Hydroxide Nanoparticles and Mesoporous Mixed Metal Oxide Electrocatalysts for the Oxygen Evolution Reaction

“…One option for cost reduction is the development of nanosized non-noble metal electrocatalysts that offer a large surface area and an excellent catalytic activity. For both the HER and OER, nickel, iron, and cobalt are often explored as potential electrocatalysts with catalytic activities that can match those of noble metal benchmarks, such as platinum and iridium. − …”

Porous Ni3S2–Co9S8 Carbon Aerogels Derived from Carrageenan/NiCo-MOF Hydrogels as an Efficient Electrocatalyst for Oxygen Evolution in Rechargeable Zn–Air Batteries

“…The massive exploitation and rapid consumption of petroleum have caused continuous harm to the environment, such as the greenhouse effect, light pollution, water pollution, etc. There is no doubt that the continued use of traditional fossil fuels will aggravate these problems. − Due to their advantages of high theoretical energy density, green environment protection, high safety, and low cost, zinc–air batteries have attracted attention from many scientists in the fields of energy conversion and wearable batteries, and oxygen evolution reaction (OER) plays a crucial part in zinc–air batteries. − At present, the oxides of precious metals Ir and Ru are the most widespread catalysts, their lack of resources, high cost of use, and poor stability force researchers to continue to explore cheap, efficient, and stable OER catalysts. − Nevertheless, because the OER process is influenced by the complicated reaction process, the overpotential is extremely high. , Therefore, developing an efficient electrocatalyst is an important method to reduce the OER overpotential and promote the rapid reaction. − Transition metal sulfides (TMSs) are rich in resources with excellent performance, , and the synergistic effect of transition metal sulfides and the heteroatom-doped carbon material can improve the conductivity of sulfide, avoid the occurrence of aggregation phenomenon, and thus improve the electrochemical activity …”