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Transition metal phosphides have been widely studied because of their low cost and good conductivity, attempting to replace precious metal-based materials as new electrochemical catalysts for oxygen evolution reaction. However, the existing high-performance phosphide catalysts for oxygen evolution reaction have bottlenecks such as difficulty to accurately determine the components and the catalytic mechanism. Therefore, in this study, we designed and synthesized FeP/CoP heterogeneous materials with a unique porous morphology as OER catalysts. The as-prepared heterogeneous materials have excellent OER catalytic activity and stability. The overpotential at 10 mA cm−2 is only 266 mV, and the Tafel slope is 60.86 mV dec−1. We believe that the good catalytic performance of the as-prepared material is mainly due to the unique morphology and redistribution of interfacial charges. The results of this study provide new ideas for designing efficient metal phosphide-based OER catalysts. [ABSTRACT FROM AUTHOR]

The oxygen evolution reaction is a key step in controlling the efficiency and stability of water electrolysis. The development of high-efficiency, energy-saving catalysts that can be used at an industrial scale is currently a major challenge. In this paper, the complex reaction of oxalic acid, ferrous chloride, and cobalt chloride in N,N-dimethylacetamide solution is used to generate an oxalic acid complex, which is then glued with polyvinylpyrrolidone and sintered to generate a bimetallic alloy catalyst. According to electrochemical tests, the obtained FeCo-2K30 has excellent activity and stability in alkaline electrolytes. Specifically, FeCo-2K30 has an overpotential of 313 mV at 10 mA cm−2 and a Tafel slope of 58 mV dec−1. Its catalytic performance is comparable to that of noble metal electrocatalysts. [ABSTRACT FROM AUTHOR]

The NiFe layered-double-hydroxide (NiFe-LDH) and the NiFe metal–organic framework (NiFe-MOF) demonstrate the best catalytic activity among NiFe-based materials for the oxygen evolution reaction (OER), which is important for efficient hydrogen production. However, the preparation processes of these materials are usually cumbersome and have a low yield, which eliminates their most critical advantage of being low cost. We propose a method for rapidly and efficiently preparing porous (Ni0.5Fe0.5)C2O4 nanorods with an excellent OER catalytic performance. The overpotential of (Ni0.5Fe0.5)C2O4 is 266 mV at 20 mA cm−2 under alkaline conditions, and the Tafel slope is 54.39 mV dec−1. Furthermore, analysis of the changes in the surface properties of the material before and after catalysis determined that the real active material is (Ni0.5Fe0.5)(OH)x(C2O4)1−x. Using a simple scaled-up experiment, (Ni0.5Fe0.5)C2O4 is mass-produced (40 g) via direct synthesis in 5 min. The composition and performance of the mass-produced sample are analysed under the same conditions, and (Ni0.5Fe0.5)C2O4 still has a good catalytic performance and its composition has not changed. The efficient synthesis of (Ni0.5Fe0.5)C2O4 nanorods with a porous structure provides a new option for the development of commercial catalysts using non-precious metals. [ABSTRACT FROM AUTHOR]

Transition metal oxides with spinel structures prepared using the traditional method have defects, including a small specific surface area, large particle size and poor conductivity. These defects considerably limit their catalytic activity in oxygen evolution reactions (OERs). This study involves the preparation of manganese iron oxide modified using flaky cobalt phosphide. The obtained product exhibits good OER catalytic performance in a 1 M alkaline solution, which shows a low overpotential of 320 mV for the OER at 50 mA cm−2. Furthermore, modified manganese iron oxide exhibits a low Tafel slope of 65.58 mVdec−1. After the introduction of flaky cobalt phosphide, the increase of the active area and conductivity of manganese iron oxide significantly improves the OER performance of the sample. The OER performance of transition metal oxides with spinel structures can be further improved using the proposed method. [ABSTRACT FROM AUTHOR]

A new and simple method to fabricate magnetic Fe4N/Fe3C samples is reported. Meanwhile, pure phase iron carbides (θ-Fe3C and χ-Fe5C2) were obtained by controlling experimental conditions. The structures, magnetic properties, and morphology of the samples were investigated according to the generalized analysis of X-ray diffraction, X-ray photoelectron spectroscopy, as well as transmission electron microscopy and vibrating sample magnetometry. The magnetic properties measurement revealed the remarkable magnetic properties of the samples at 2 and 300 K. The application of the prepared samples as catalysts for oxygen evolution reaction was also investigated in alkaline solution. This simple and convenient route provides a new path to fabricate other metal nitrides and carbides. [ABSTRACT FROM AUTHOR]

[Display omitted] • Muti-channel iron-cobalt hydroxide was obtained at room temperature. • The lowest overpotential is 260 mV@10 mA·cm−2. • The obtained iron-cobalt hydroxide catalyst has satisfactory catalytic stability. Binary transition metal hydroxides have been widely studied as catalysts for oxygen evolution reaction under alkaline conditions due to their advantages of simple preparation and low cost. Although many studies have confirmed that these materials have excellent catalytic activity, their catalytic stability is still controversial. In this study, we obtained muti-channel Fe-Co binary hydroxides through a simple room-temperature ion-exchange process. The prepared materials have good OER catalytic activity under alkaline conditions, the lowest overpotential is 260 mV@10 mA·cm−2. And the prepared materials also have impressive OER catalytic stability, which can still maintain 70 % catalytic activity after 72 h of catalytic process. [ABSTRACT FROM AUTHOR]