Green Synthesis and Characterization of Nickel Tungsten Bimetallic Oxide Nanoparticles via Microwave Irradiation Technique

Nickel tungsten bimetallic oxide nanoparticles were synthesised in ethylene glycol using microwave irradiation technique. Nickel and tungsten oxide nanoparticles were synthesised separately using microwave assisted polyol synthesis method. The respective systems are combined together in ratio 1:1 molar and are subjected to microwave irradiation to get Ni-W bimetallic oxide. The structure and composition of nanoparticles were characterised by UV-Visible Spectroscopy, FT-IR Spectroscopy, X-Ray Diffraction (XRD), Energy Dispersion Spectroscopy (EDS), Transmission Electron Microscopy (TEM), Photoluminescence Spectroscopy (PL) and Magnetic Susceptibility measurements. From the XRD and FTIR measurements, nanocrystalline Wolframite structure of Ni-W bimetallic oxide nanoparticles was established. The emperical formula of the nanoparticle is found as Ni0.4W0.6O2.6. The composition may be varied by changing the ratio of Ni and W. A maximum absorbance of 385nm was obtained in UV-Visible spectrum and three emission peaks were obtained in the visible region of photoluminescent studies. Further studies can be done on the catalytic and electrochromic properties of the substance.

The Production of Liquid Fuel Products by the Catalytic Hydroliquefaction of Sapropels Using Nickel and Nickel-Tungsten Catalysts

Ni catalysts with the carbon-mineral supports obtained from sapropel were synthesized and studied in the catalytic hydroliquefaction of sapropel. It was found that catalysts with the supports obtained from mineral sapropel are more active as compared to those based on organic sapropel; therewith, bimetallic NiW catalysts showed a higher activity than monometallic nickel, irrespective of the support nature. The conversion of the organic matter of sapropel and the composition of liquid products are affected by both the features of supported metal and the composition of support. The liquid products of hydroliquefaction contain mostly the nitrogen- and oxygen-containing compounds. The maximum yield of С5-С21 hydrocarbons is achieved for the catalysts with the supports obtained from mineral sapropel. The composition of the liquid products of sapropel hydroliquefaction is similar to that of biofuels obtained from other renewable sources; such products can be introduced in the known schemes of further processing.

Ternary nickel–tungsten–copper alloy rivals platinum for catalyzing alkaline hydrogen oxidation

Operating fuel cells in alkaline environments permits the use of platinum-group-metal-free (PGM-free) catalysts and inexpensive bipolar plates, leading to significant cost reduction. Of the PGM-free catalysts explored, however, only a few nickel-based materials are active for catalyzing the hydrogen oxidation reaction (HOR) in alkali; moreover, these catalysts deactivate rapidly at high anode potentials owing to nickel hydroxide formation. Here we describe that a nickel–tungsten–copper (Ni5.2WCu2.2) ternary alloy showing HOR activity rivals Pt/C benchmark in alkaline electrolyte. Importantly, we achieved a high anode potential up to 0.3 V versus reversible hydrogen electrode on this catalyst with good operational stability over 20 h. The catalyst also displays excellent CO-tolerant ability that Pt/C catalyst lacks. Experimental and theoretical studies uncover that nickel, tungsten, and copper play in synergy to create a favorable alloying surface for optimized hydrogen and hydroxyl bindings, as well as for the improved oxidation resistance, which result in the HOR enhancement.