NiMo–NiCu Inexpensive Composite with High Activity for Hydrogen Evolution Reaction

Abstract

In this work, the effect of copper addition on NiMo coating is evaluated in regard to the hydrogen evolution reaction (HER). NiMo and NiMo–NiCu composites are prepared by a simple coelectrodeposition process. The effect of Cu on deposit characters were tested by varying it in the range of 0.06–0.20 molar ratio. Copper addition promotes the growth of a new crystalline phase: NiCu. Also, the copper addition changed the composite surface. NiMo–NiCu0.12 shows a surface roughness 30 times higher than the NiMo material. NiMo–NiCu materials present higher activity toward HER, larger electroactive area, and higher stability in continuous water electrolysis than NiMo catalysts, as demonstrated by Tafel curves, electrochemical impedance spectroscopy measurements, and polarization tests. The combination of the large electroactive area due to the copper addition, the synergism between Ni–Mo, and the presence of Ni and Mo oxides on the surface results in catalyst with excellent features for HER application.

Transition Metal/Metal Oxide Interface (Ni–Mo–O/Ni4Mo) Stabilized on N-Doped Carbon Paper for Enhanced Hydrogen Evolution Reaction in Alkaline Conditions

“…EIS measurements were also conducted to provide more information at the electrode−electrolyte interface (Figure 3c). Note that the first semicircle in the highfrequency region of the Nyquist plots was related to the electrode texture and was independent of the kinetics of the faradaic process, 33 These results confirm that the metal/metal oxide did not change.…”

“…EIS measurements were also conducted to provide more information at the electrode–electrolyte interface (Figure c). Note that the first semicircle in the high-frequency region of the Nyquist plots was related to the electrode texture and was independent of the kinetics of the faradaic process, while the second semicircle in the low-frequency region refers to the charge transfer resistance ( R ct ) in the HER. As expected, the Ni–Mo–O/Ni 4 Mo@NC exhibits a smaller R ct than that of Ni–Mo–O, suggesting the fast electron transport on the Ni–Mo–O/Ni 4 Mo@NC interfaces.…”

Phytochemical-Assisted Green Synthesis of Nickel Oxide Nanoparticles for Application as Electrocatalysts in Oxygen Evolution Reaction

“…The EIS measurements for all the samples were performed with a frequency range from 0.1 Hz to 100 kHz, and the resulting Nyquist plots comprising of semicircles are presented in Figure 8. The starting point of the semicircle signifies the internal resistance (also known as solution resistance (R S )) of the catalyst, whereas the diameter of the semicircle denotes chargetransfer resistance between the electrode-electrolyte interfaces (R CT ) [26]. In terms of equivalent circuit, the depressed semicircle is represented by R S connected in series to the capacitor (Q DL ) and R CT in a parallel arrangement, as shown in Figure 8.…”

Towards Highly Efficient Chalcopyrite Photocathodes for Water Splitting: The Use of Cocatalysts beyond Pt

“…NiÀ W, NiÀ MoÀ Fe, and NiÀ MoÀ Co [78] are few examples of Ni-based alloys that have been broadly studied for HER and they can also be applied as cocatalyst in photocathodes. Recently, Santos et al [79,80] have shown that a copper insertion in NiÀ Mo and CoÀ Mo alloys can increase catalytic activity and reduce overpotential. The addition of Cu in NiÀ Mo decreased the overpotential in almost half of the values obtained for NiÀ Mo electrodes (η = À 154 mV dec À 1 for NiÀ Mo and η = À 86 mV dec À 1 for NiÀ MoÀ Cu at À 10 mA cm À 2 ).…”