Preparation And Electrocatalytic Performances Of Ni Based Catalysts

The ever increasing global warning for energy and environmental concerns has stimulated considerable research efforts to exploit renewable carbon-free energy. Hydrogen is now being vigorously pursued as a major renewable energy carrier and an alternative potential power source for the future world, including the clean production and safety on board storage. A renewable and scalable source for the hydrogen production would be the splitting of water by either sunlight or electricity because of the relevance to renewable energy storage and the potential for providing energy without CO2emission. Nickel-molybdenum (Ni-Mo) alloys are well-known non-precious metal electrocatalyst for hydrogen production in alkaline electrolytes because of the increased intrinsic electrocatalytic activity compared to pure Ni, appropriate binding energy to hydrogen, and good corrosion resistance in aggressive environment. 3D nanoporous Ni-Mo alloy with ultrahigh electrocatalytic activity and prominent stability for hydrogen evolution reaction (HER) was successfully achieved though a facile and effective electrodeposition method. By optimizing Ni:Mo ratio, electrodeposition current density and electrodeposition time,3D nanoporous Ni-Mo alloy exhibited compent-dependent enhanced electrocatalytic activity.3D nanoporous Ni-Mo alloy fabricated at the current density of200mA cm-2and electrodeposition time of3600s exhibited the highest alkaline HER electrocatalytic activity with lowest overpotential (10mV vs. RHE) and durable excellent electrochemical stability, which was best among those ever reported non-noble metal electrocatalysts. The improved HER performance of Ni-Mo electrocatalyst with negligible overpotential and much higher current density compared to that of Pt/C, could be attributed to the proper Ni:Mo ratio (4:1), the large surface area, and the well-constructed catalyst made by in situ growth method (under water "superaerophilic").3D nanoporous Ni-Mo electrocatalyst for the hydrogen oxydation reaction (HOR) and oxygen evolution reaction (OER) have also been investigated.The Ni-Mo-Co alloy with prominent electrocatalytic activity for HER has been fabricated by a facile and effective electrodeposition. Comparing to Ni-Mo, the overpotential of Ni-Mo-Co alloy electrocatalyst can be discreased30mV at the same current density, suggesting it to be the effective and low-cost electrocatalytic nanomaterial in new generation of electrochemical devices for providing safe, clean and sustainable hydrogen-based energy system and be the alternative to precious Pt.The Ni-Mo/Si nanowire was firstly achieved through a combined technology of chemical etching method and electrodeposition. As shown in the field-emission scanning electron microscope (SEM), with the increased electrodeposition current, the Ni-Mo/Si nanowire was changed into the Ni-Mo/Si coarse film. The linear sweep voltammogram (LSV) was utilized to evaluate the HER activity. With the increased current density, the activity for HER was increased, which was attributed to the Ni:Mo ratios. Ni-Mo/Si coarse film exhibited no response to the sunlight, which was attibuted to the heavy coverage of Si substrate.The high theoretical capacitance and good electrochemical properties prompt LaNi5widely used in hydrogen storage through reversible sorption processes. The intermediate of LaNi5was firstly achieved by a simple and facile solvothermal technique. The TEM system, X-ray powder diffraction patterns (XRD), cyclic voltammetry (CV), galvanostatic charge and discharge curves were utilized to characterize the LaNi5alloy. As revealed in the TEM, the intermediate was consisted of nanohollow sphere. The intermediate was a mixed phase, which was confirmed by the XRD data. The hydrogen storage properties of LaNi5 should be further improved by optimizing experimental conditions.