Study of Pt-free anode catalysts for anion exchange membrane fuel cells

Single Crystalline Ultrathin Nickel-Cobalt Alloy Nanosheets Array for Direct Hydrazine Fuel Cells

Ultrathin 2D metal alloy nanomaterials have great potential applications but their controlled syntheses are limited to few noble metal based systems. Herein Ni x Co1-x alloy nanosheets with ultrathin (sub-3 nm) single-crystalline 2D structure are synthesized through a topochemical reduction method. Moreover, the optimized composition Ni0.6Co0.4 alloy nanosheets array exhibits excellent performances for hydrazine oxidation reaction and direct hydrazine fuel cells.

Effect of Surface Ion Conductivity of Anion Exchange Membranes on Fuel Cell Performance

Anion conductivity at the surfaces of two anion-exchange membranes (AEMs), quaternized ammonium poly(arylene ether) multiblock copolymer (QPE-bl-3) and quaternized ammonium poly(arylene perfluoro-alkylene) copolymer (QPAF-1), synthesized by our group was investigated using current-sensing atomic force microscopy under purified air at various relative humidities. The anion-conducting spots were distributed inhomogeneously on the surface of QPE-bl-3, and the total areas of the anion-conducting spots and the current at each spot increased with humidity. The anion-conductive areas on QPAF-1 were found on the entire surface even at a low humidity. Distribution of the anion-conducting spots on the membrane was found to directly affect the performance of an AEM fuel cell.

Liquid–liquid interface-mediated room-temperature synthesis of amorphous NiCo pompoms from ultrathin nanosheets with high catalytic activity for hydrazine oxidation

Ni_xCo_y alloy pompoms formed by the aggregation of nano ultrathin sheets were prepared by simultaneous reduction of NiCl₂ and CoCl₂ with NaBH₄via a liquid–liquid interface reaction.

Novel quaternized mesoporous silica nanoparticle modified polysulfone-based composite anion exchange membranes for alkaline fuel cells

A polysulfone-based composite membrane with QMSNs showed improved conductivity, good morphologies without phase separation, acceptable mechanical properties, and alkaline and oxide resistance, opening up a new way to fabricate organic–inorganic composite AEMs.

Carbon segregation-induced highly metallic ni nanoparticles for electrocatalytic oxidation of hydrazine in alkaline media

The important roles of Ni in electrocatalytic reactions such as hydrazine oxidation are limited largely by high oxidation states because of its intrinsically high oxophilicity. Here, we report the synthesis and properties of highly metallic Ni nanoparticles (NPs) on carbon black supports. We discovered that the heat treatment of as-prepared Ni NPs with an average particle size of 5.8 nm produced highly metallic Ni NPs covered with thin carbon shells, with negligible particle coarsening. The carbon shells were formed by the segregation of carbons in the Ni lattice to the surface of the Ni NPs, leaving highly metallic Ni NPs. X-ray photoelectron spectroscopic analyses revealed that the atomic ratio of metallic Ni increased from 19.2 to 71.7% as a result of the heat treatment. The NPs exhibited higher electrocatalytic activities toward the hydrazine oxidation reaction in alkaline solution, as compared to those of the as-prepared Ni NPs and commercial Ni powders.

Steam Reforming of Glycerol for Hydrogen Production over Ni/SiO2 Catalyst

The performance of Ni/SiO2 catalyst for glycerol reforming has been investigated in fixed-bed reactor using careful tailoring of the operational conditions. In this paper, a commercial Engelhard catalyst has been sized and compared to gas product distribution versus catalyst size, water-to-carbon ratio, and stability of the catalyst system. Ni/SiO2 catalysts of three sizes (2×2, 2×4, and 3×5 mm) are evaluated using glycerol: water mixture at 600°C to produce 2 L H2 g−1 cat h−1. The results indicate that 3×5 mm size pellet is showing minimum coking and maintaining same level of conversion even after several hours of reforming activity. Whereas studies on 2×2 and 2×4 mm pellets indicate that carbon formation is affecting the reforming activity. Under accelerated aging studies, with 1 : 9 molar ratio of glycerol to water, 3 mg carbon g−1 cat h−1 was generated in 20 cycles, whereas 1 : 18 feed produced only 1.5 mg carbon g−1 cat h−1 during the same cycles of operation. The catalysts were characterized before and after evaluation by X-ray diffraction (XRD), BET surface area, scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDAX), CHNS analysis, transmission electron microscopy (TEM), and X-ray photo electron spectroscopy (XPS).