NOPR Collection:

Electrodeposition of platinum-iridium nanoparticles on carbon nanotubes and their electrocatalytic oxidation of glucose

Sun, 01 Oct 2017 00:00:00 GMT

Title: Electrodeposition of platinum-iridium nanoparticles on carbon nanotubes and their electrocatalytic oxidation of glucose Authors: Wu, Bohua; Zhu, Jiajin; Li, Xue; Zhou, Ting; Mao, Liqiu; Xiong, Shanxin Abstract: Platinum-iridium (PtIr) nanoparticles (NPs) have been anchored on the surface of carbon nanotubes by potentiostatic electrodeposition in 0.5 M H₂SO₄+0.5 M glycerol aqueous solution. The surface and composition of the PtIr NPs/CNTs nanohybrids have been characterized by transmission electron microscopy and energy dispersive spectroscopy, respectively. The electrocatalytic properties of the PtIr NPs/CNTs catalysts for glucose oxidation have been investigated by cyclic voltammetry and chronoamperometry. The size of the PtIr NPs can be controlled from 3.0–7.0 nm by controlling the amount of Ir. In particular, the PtIr NPs has been optimized at 1:1 Pt/Ir atomic ratio. The as-prepared PtIr (1:1) NPs/CNTs catalysts possess unique properties including small size of PtIr NPs, excellent dispersion, high electrochemical active surface area and exhibit high activity towards glucose oxidation. For comparison, Pt NPs/CNTs catalysts have also been prepared under the same controlled procedure. In the absence of Ir, Pt NPs are also uniformly dispersed on the CNTs, and their average diameter is 4.0±0.5 nm, close to that of PtIr NPs. Further, addition of Ir makes PtIr (1:1) NPs/CNTs catalysts superior to Pt NPs/CNTs catalysts in term of better long-term stability and higher catalytic efficiency of glucose oxidation. The PtIr (1:1) NPs/CNTs catalysts are proved to be promising anode catalysts for direct glucose fuel cells. Page(s): 1007-1013

Phthalate precursor mediated synthesis of cadmium oxide nanoparticles and their photocatalytic application

Sun, 01 Oct 2017 00:00:00 GMT

Title: Phthalate precursor mediated synthesis of cadmium oxide nanoparticles and their photocatalytic application Authors: Narulkar, Dattaprasad D; Gaude, Teena A Jalmi; Dhuri, Sunder N Abstract: Cadmium oxide samples have been prepared by thermal decomposition of their precursors [Cd(pht)(H₂O)] (1), [Cd(pht)(Im)(H₂O)_0.5] (2), [Cd(pht)(MeIm)] (3) and [Cd(pht)(bpy)(H₂O)₂] (4) respectively (pht = phthalate, Im = imidazole, MeIm = 2-methylimidazole, bpy = 2,2′-bipyridine). Precursor 1 has been synthesized by a reaction of in situ generated disodium phthalate with cadmium acetate, while 2-4 were prepared by adding Im, MeIm and bpy respectively, to the solution of 1. All compounds are characterized by elemental analysis, infrared spectroscopy and thermal techniques (TG/DTA). The particle size of CdO nanoparticles ranges from 53–62 nm as evident by PXRD, SEM/ TEM studies. The band gap values for CdO samples lie in the range 1.95–1.98 eV. The photolytic degradation rates of methylene blue by CdO are inversely proportional to the crystallite sizes of CdO samples. Page(s): 1014-1020

Preparation, characterization and photocatalytic activity of silicon and sulfur codoped mesoporous titanium dioxide photocatalyst

Sun, 01 Oct 2017 00:00:00 GMT

Title: Preparation, characterization and photocatalytic activity of silicon and sulfur codoped mesoporous titanium dioxide photocatalyst Authors: Shi, Zhongliang; Wang, Xu; Yao, Shuhua Abstract: A series of mesoporous titanium dioxide (MTiO₂) photocatalysts codoped with silicon and sulfur has been prepared by a template method using tetraethyl orthosilicate, thiourea and tetrabutyl titanate (Ti(OC₄H₉)₄) as precursors and Pluronic P123 as template. The photoabsorbance of the prepared photocatalysts has been measured by UV-vis diffusive reflectance spectroscopy and its microstructure characterized using scanning electron microscopy, diffraction (XRD) and N₂ adsorption-desorption measurements. The microcrystal of the codoped photocatalyst consistest of anatase phase and is present in the form of almost spherical particle. The photocatalytic activity has been studied by photodegradation of methyl blue in aqueous solution under UV and visible light irradiation. The results show that the amount of dopants, silicon and sulfur, influence the photoactivity. The photocatalyst codoped with 1 mol% silicon and 2 mol% sulfur exhibites the highest photoactivity. The synergistic effect of silicon and sulfur codoping in improves the photocatalytic activity considerably. Page(s): 1021-1027

Structure and photocatalytic activity of bismuth tungstate nanoparticles synthesized by one-step solvothermal method

Sun, 01 Oct 2017 00:00:00 GMT

Title: Structure and photocatalytic activity of bismuth tungstate nanoparticles synthesized by one-step solvothermal method Authors: Zhang, Xiang-Hui Abstract: Bi₂WO₆ has been synthesized by water, methanol or ethylene glycol assisted solvothermal method. The physical and photophysical properties of the as-prepared samples are characterized by XRD, UV-vis, SEM and BET surface area measurements. XRD results show orthorhombic Bi₂WO₆ with the average crystallite size of about 9.2 nm, obtained using ethylene glycol as the reaction solvent. By substituting ethylene glycol for deionized water or methanol as solvent, the size of Bi₂WO₆ increases. BET results indicate that the Bi₂WO₆ sample prepared in ethylene glycol has the largest surface area (56.5 m² g^–1). The photocatalytic activities of as-prepared samples have been evaluated by the degradation of methylene blue in an aqueous solution under visible light irradiation. The degradation ratio of MB over Bi₂WO₆ synthesized in ethylene glycol (97.1%) is much higher than that over Bi₂WO₆ synthesized in deionized water (82.8%) and methanol (50.0%) within 120 min. This may be attributed to its appropriate energy band structure, small crystallite size, and high surface area. Page(s): 1028-1033