Electrodeposited tungsten-rich Ni-W, Co-W and Fe-W cathodes for efficient hydrogen evolution in alkaline medium

Comparative Analysis of Metal Electrodeposition Rates towards Formation of High-Entropy WFeCoNiCu Alloy

This study presents a calculation and comparison of Fe, Co, Ni and Cu deposition rates in the tungsten codeposition process based on the electrodeposition of numerous tungsten alloys. Eight different tungsten alloys containing from two to five metals were electrodeposited in constant conditions in order to compare the exact reduction rates. The calculated rates enabled control of the alloy composition precise enough to obtain a high-entropy WFeCoNiCu alloy with a well-balanced composition. The introduction of copper to form the quinternary alloy was found to catalyze the whole process, increasing the deposition rates of all the components of the high-entropy alloy.

In situ fabrication of a 3D self-supported porous Ni-Mo-Cu catalyst for an efficient hydrogen evolution reaction

It is still a challenge to develop very effective and stable non-noble catalysts for the hydrogen evolution reaction (HER). Here, a self-supported porous Ni-Mo-Cu coating is prepared by the dynamic hydrogen bubble template (DHBT) method. This three-dimensional (3D) porous Ni-Mo-Cu coating can offer a large surface area, which helps expose more active sites and promote the transmission of electrons and materials. To achieve this, the 3D porous Ni-Mo-Cu coating catalyst requires a low overpotential value of 70 mV at 10 mA cm^-2 in 1 M KOH and stable catalytic properties at a high current density of 500 mA cm^-2 for more than 10 h with no obvious evidence of degradation. DFT calculations show the source of the excellent catalytic performance of the 3D porous Ni-Mo-Cu catalyst in alkaline media, including the kinetic energy and adsorption energy. This work provides significant insight into the design of efficient 3D porous materials.

Preparation and Electrochemical Behavior of an Amorphous Co–Mo Coating with a High Content of Mo

At present, alloy materials are being widely used as wear-resistant coatings due to good mechanical properties. In this paper, electrodeposition was used to prepare a Co–Mo coating. The influence of parameters on the phase, morphology, composition, and property of the coating has been studied, and the electrochemical mechanism has been deeply studied. The study of process parameters found that when the concentration of Na2Mo4 is 0.05 mol/L, the concentration of C6H5Na3O7 is 0.15 mol/L, the pH of the solution is 7, and the temperature is 50 °C, the content of Mo in a Co–Mo coating is 39.56%, and the microhardness reaches the maximum value of 503 HV. The study of electrochemical behavior found that the optimization of process parameters bringsa positive shift in the reduction potential, an increase in the exchange current density, and a decrease in charge transfer impedance. The microhardness of a Co–Mo coating prepared with the leaching solution of Mo-containing waste after component control of the plating solution is 483.6 HV, which is valuable to the high-value recycling of Mo secondary resources.