Nickel

About: Nickel is a research topic. Over the lifetime, 79308 publications have been published within this topic receiving 1210058 citations. The topic is also known as: Ni & element 28.

Study of nickel-molybdenum-.gamma.-aluminum oxide catalysts by x-ray photoelectron and Raman spectroscopy. Comparison with cobalt-molybdenum-.gamma.-aluminum oxide catalysts

Abstract: Several series of nickel (or Co) molybdenum oxide catalysts supported on ..gamma..-Al/sub 2/O/sub 3/ have been studied by X-ray photoelectron and Raman spectroscopy. The combination of these two techniques is a complementary approach to the alumina coverage, the nature of the deposited species, and the interaction between these species. In particular, the characteristics of the monolayer coverage by the nickel species appear somewhat different from cobalt in systems without molybdenum. When molybdenum is present, formation of a phase similar to (a) NiMoO/sub 4/ is observed. No bulk NiO or Ni(OH)/sub 2/ phases are detected. Comparison with Co-Mo or Ni-Mo-..gamma..-Al/sub 2/O/sub 3/ industrial catalysts is also presented.

Copper–Nickel Nitride Nanosheets as Efficient Bifunctional Catalysts for Hydrazine-Assisted Electrolytic Hydrogen Production

Abstract: DOI: 10.1002/aenm.201900390 regarded as an ideal alternative energy carrier due to its purity and sustainability.[3,4] Production of hydrogen by electrochemical water splitting in alkaline electrolyte which involves two half reactions, namely, the hydrogen evolution reaction (HER, 4H2O + 4e− → 2H2 + 4OH−) and oxygen evolution reaction (OER, 4OH− → O2 + 2H2O + 4e−), seems a promising and environmentally benign approach.[5–7] At present, precious metal electrocatalysts, such as platinum-based and iridium or ruthenium-based materials are regarded as the state-of-the-art catalysts for HER and OER, respectively.[8–10] However, the high cost, low abundance, and poor stability of these catalysts significantly hinder their extensive applications in commercial electrolyzers. Consequently, extensive studies have been conducted to develop low-cost, high-activity electrocatalysts based on transitional metal materials, including metal alloys,[11,12] chalcogenides,[13–17] phosphides,[18–22] carbides,[23–25] and nitrides[26–31] for HER, and metal oxides,[32,33] hydroxides,[34] oxyhydroxides,[35,36] selenides,[37–41] and perovskites[42] for OER. Nevertheless, the operation voltage of water splitting in alkaline electrolyte at 10 mA cm−2 is still larger than 1.4 V because of the sluggish anodic OER kinetics.[18–20,34] OER is quite a complicated process as it involves four proton-coupled electrons transfer steps, OH bond breaking and OO bond Electrocatalytic water splitting is one of the sustainable and promising strategies to generate hydrogen fuel but still remains a great challenge because of the sluggish anodic oxygen evolution reaction (OER). A very effective approach to dramatically decrease the input cell voltage of water electrolysis is to replace the anodic OER with hydrazine oxidation reaction (HzOR) due to its lower thermodynamic oxidation potential. Therefore, developing the lowcost and efficient HzOR catalysts, coupled with the cathodic hydrogen evolution reaction (HER), is tremendously important for energy-saving electrolytic hydrogen production. Herein, a new-type of copper–nickel nitride (Cu1Ni2-N) with rich Cu4N/Ni3N interface is rationally constructed on carbon fiber cloth. The 3D electrode exhibits extraordinary HER performance with an overpotential of 71.4 mV at 10 mA cm−2 in 1.0 m KOH, simultaneously delivering an ultralow potential of 0.5 mV at 10 mA cm−2 for HzOR in a 1.0 m KOH/0.5 m hydrazine electrolyte. Moreover, the electrolytic cell utilizing the synthesized Cu1Ni2-N electrode as both the cathode and anode display a cell voltage of 0.24 V at 10 mA cm−2 with an excellent stability over 75 h. The present work develops the promising copper–nickel-based nitride as a bifunctional electrocatalyst through hydrazine-assistance for energy-saving electrolytic hydrogen production. Water Electrolysis