Experimental Study of Localized Electrochemical Deposition of Ni-Cu Alloy Using a Moving Anode

Fabrication and characterization of NiCu/GO and NiCu/rGO nanocomposites for fuel cell application

This study investigated the electrochemical behavior of NiCu, NiCu/GO, and NiCu/rGO nanocomposites designed by combining a modified Hummers' method and hydrothermal technique. The prepared nanocomposites are tested as electrocatalysts in direct alcohol oxidation fuel cells (DAFCs) to identify the role of GO and rGO as catalyst supports for the enhancement of the NiCu composite performance. The production of the NiCu/GO and NiCu/rGO composites was demonstrated by FTIR spectroscopy, EDX, and SEM analyses. In DAFCs experiments, NiCu/rGO has better catalytic activity than pure NiCu and NiCu/GO composites, whereas the use of rGO and GO as supports enhances the performance of NiCu by 468.2% and 377.7% in methanol and 255.6% and 105.9% in ethanol, respectively. The higher performance was caused by the increased density of active dots and the combined electronic effects in the designed catalysts. The stabilities of the catalysts and charge carriers' dynamics are studied using chronoamperometry and electrochemical impedance spectroscopy.

The one-pot synthesis of CuNi nanoparticles with a Ni-rich surface for the electrocatalytic methanol oxidation reaction

The use of fuel cells is one of the most promising renewable energy strategies, but they still suffer from many limitations. The high mass enthalpy of hydrogen as a fuel comes at the cost of inconveniences and risks associated with storage, transportation and utilization, while the high performance of Pt catalysts in commercial fuel cells is limited by their high cost, low earth abundance, and poor stability as a result of CO intermediate poisoning. To circumvent these dilemmas, direct methanol fuel cells (DMFCs) were developed, using methanol as a fuel and Ni as the anode catalyst. Thanks to the condensed form of the fuel, DMFCs are considered as the most promising fuel-cell solution for portable electronic devices. Usually, other elements have to be introduced into Ni-based catalysts to modify the active sites to provide better alternatives to pristine Ni metal in terms of activity and stability. In this study, we provide a mild synthetic method for the preparation of CuNi alloy nanoparticles. The proper alloying ratio leads to the suitable modification of the electronic structure of Ni, which promotes the MOR catalytic reaction on the NiCu alloy. The NiCu alloy catalyst exhibits a mass current density of 1028 mA mg_metal^-1 for the MOR at 1.55 V (vs. RHE), which is among the best values obtained from similarly prepared Ni-based catalysts.