Cu2O@Fe-Ni3S2 nanoflower in situ grown on copper foam at room temperature as an excellent oxygen evolution electrocatalyst

Fe-Doped Ni3S2 Induces Self-Reconstruction for Urea-Assisted Water Electrolysis Enhancement

Urea oxidation reaction (UOR) is an attractive alternative anodic reaction to oxygen evolution reaction (OER) for its low thermodynamic potential (0.37 V vs RHE). A major challenge that prohibits its practical application is the six-electron transfer process during UOR, demanding enhancements in the catalytic activity. Herein, a Fe-doped Ni3S2 catalyst with a uniform flower-like structure is synthesized in situ on nickel foam via a simple one-step hydrothermal method. The electrochemical properties of Fe-Ni3S2 are significantly improved since a current density of 10 mA cm-2 only requires a 1.33 V potential and remains stable for 60 h. The structural characterization demonstrates a strong interaction between Fe and Ni3S2. After Fe doping, the active site increases, which promotes the formation of NiOOH on the catalyst surface, thus speeding up the UOR process. These changes are beneficial to charge transfer and optimize the adsorption energy of the intermediates. In situ EIS further confirms that Fe promotes electron transfer during the UOR process, reduces the interface resistance between the catalyst and the electrolyte, and lowers the driving voltage.

Transition Metals-Based Water Splitting Electrocatalysts on Copper-Based Substrates: The Integral Role of Morphological Properties

Electrocatalytic water splitting is a promising alternative to produce high purity hydrogen gas as the green substitute for renewable energy. Thus, development of electrocatalysts for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are vital to improve the efficiency of the water splitting process particularly based on transition metals which has been explored extensively to replace the highly active electrocatalytic activity of the iridium and ruthenium metals-based electrocatalysts. In situ growth of the material on a conductive substrate has also been proven to have the capability to lower down the overpotential value significantly. On top of that, the presence of substrate has given a massive impact on the morphology of the electrocatalyst. Among the conductive substrates that have been widely explored in the field of electrochemistry are the copper based substrates mainly copper foam, copper foil and copper mesh. Copper-based substrates possess unique properties such as low in cost, high tensile strength, excellent conductor of heat and electricity, ultraporous with well-integrated hierarchical structure and non-corrosive in nature. In this review, the recent advancements of HER and OER electrocatalysts grown on copper-based substrates has been critically discussed, focusing on their morphology, design, and preparation methods of the nanoarrays.

MIL-101 supported CeOx-modified NiPt nanoparticles as a highly efficient catalyst toward complete dehydrogenation of hydrazine borane

High hydrogen content and excellent stability at room temperature promote hydrazine borane (HB, N2H4BH3) as a promising chemical hydrogen storage material. However, the development of high efficient and selective catalysts...

Selenium-induced NiSe2@CuSe2 hierarchical heterostructure for efficient oxygen evolution reaction

Electrochemical water splitting is widely studied in the hope of solving environmental deterioration and energy shortage. The design of inexpensive metal catalysts exhibiting desired catalytic performance and durable stability for efficient oxygen evolution is the pursuit of sustainable and clean energy fields. Herein, a three-dimensional (3D) flower-like NiSe₂ primary structure, modified with highly dispersed CuSe₂ nanoclusters as the secondary structure, is obtained by regulating the growth trend of the nanosheets. Benefiting from the metallicity of selenides and the formation of a heterogeneous interface, NiSe₂@CuSe₂/NF shows comparable performance toward the oxygen evolution reaction (OER) in an alkaline environment. Upon regulating the synthesis conditions, the catalyst exhibits its optimal performance with ultralow overpotential for the OER when the Ni/Cu molar ratio is 1 : 0.2 and the hydrothermal temperature and hydrothermal time are 200 °C and 6 h, respectively. It provides a current density of 10 mA cm^-2 when a potential of 201 mV is applied without iR compensation. In this work, the hierarchical heterostructures of NiSe₂ and CuSe₂ are synthesized, which exhibit high electrocatalytic activity towards the oxygen evolution reaction and provides a new possibility for the extensive application of copper-based compounds in advanced energy fields.