O:Oxidizing agent;20667-12-3Relevant articles and documents
Temperature-programmed reduction study on calcination of nano-palladium
Yeh,Chu,Sheen,Chiang,Chou,Perng,Huang,Lee
, p. 9113 - 9117 (2001)
Pd membranes with high mechanical strengths are used to purify hydrogen in industrial scale for feedstock in petrochemical processes. The effects of calcinations treatment on samples of mono-metallic Pd and Pd77-Ag23 alloy with primary particles ～ 8 nm were studied with the TPR technique. A hydrogen-consumption at low temperature and a hydrogen-desorption at high temperature were observed from obtained TPR traces. The extent of oxidation on both samples increased with the calcinations temperature, i.e., oxygen adsorption on the surface of primary particles at To o > 573 K. The temperature required for a reduction of oxidized palladium by hydrogen was generally low. Tr = 150 K for oxygen chemisorbed on nano-palladium but raised over 260 K for oxide anions in the PdO structure. Primary particles of nano-palladium retained their size of 8 nm upon calcinations at To o > 673 K. Incorporation of oxygen into sublayers of Pd crystallites was promoted by alloy with silver.
Low-temperature synthesis of single crystalline Ag2S nanowires on silver substrates
Wen, Xiaogang,Wang, Shuhua,Xie, Yutao,Li, Xiao-Yuan,Yang, Shihe
, p. 10100 - 10106 (2005)
We report on the successful synthesis of silver sulfide (Ag2S) nanowires by a simple and mild gas - solid reaction approach. For the nanowire synthesis, a preoxidized silver substrate is exposed to an atmosphere of an O2/H2S mixture at room temperature or slightly above. The resulting Ag2S nanowires are phase pure with a monoclinic crystal structure and have diameters of a few tens of nanometers and lengths up to 100 ??m. The influence of reaction conditions on the diameter, length, and morphology of the Ag2S nanowires has been studied by a number of structural and spectroscopic techniques. The nanowire growth mechanism on the Ag substrate has been discussed, which is likely characterized by continuous deposition at the tip. Additionally, we demonstrate thinning and cutting of individual Ag2S nanowires with electron beams and laser beams, which are potentially useful for nanowire manipulation and engineering. ? 2005 American Chemical Society.
Kinetic study of the reactions of gas phase Pd(a1S0), Ag(5s 2S1/2), Au(6s 2S1/2), Cd(5s2 1S0, and Hg(6s2 1S0) atoms with nitrous oxide
Campbell, Mark L.
, p. 3048 - 3053 (2003)
The reactivity of gas-phase Pd(a1S0), Ag(5s 2S1/2), Au(6s 2S1/2), Cd(5s2 1S0), and Hg(6s2 1S0) with N2O as a function of temperature and pressure is reported. The transition metal atoms were produced by the photodissociation of an appropriate precursor molecule and detected by laser-induced fluorescence. The reaction of palladium with N2O is pressure dependent indicating adduct formation. The room-temperature limiting low-pressure third-order rate constant is (2.5 ± 0.8) × 10-30 molecule-2 cm6 s-1 in argon buffer. The limiting low-pressure third-order rate constant can be expressed as log k0(T) = -219.06 + 152(log T) - 30.5(log T)2 molecule-2 cm6 s-1 over the temperature range 294-523 K. The reactions of ground-state silver, gold, cadmium, and mercury with N2O are very slow, and only upper limits for the rate constants can be reported for these reactions.
Skeleton pseudomorphs of nanostructured silver for the surface-enhanced Raman spectroscopy
Semenova, Anna A.,Savilov, Sergey V.,Baranchikov, Alexander E.,Ivanov, Vladimir K.,Goodilin, Eugene A.
, p. 395 - 397 (2019)
Pseudomorphs (mesocages) of metallic silver were prepared via either a shape-preserving reduction of polyhedral Ag2O precursors with H2O2 in aqueous ammonia or an ultrasonic spray pyrolysis of aqueous diamminesilver(i) hydroxide. Both the materials were revealed as suitable for the direct analysis at 0.1–1 μm concentrations of oil pollutants and pharmaceutical substances using surface-enhanced Raman spectroscopy due to their unique morphology providing either a larger surface area for sorption of analytes or additional ‘hot spots’ resulting in the enhancement factors of 106–108.
Single-crystal-to-single-crystal conversions of two metal-mediated photoreactive coordination polymers based on stereoselective [2 + 2] photocycloaddition reactions
Chen, Jing-Min,Zhou, Qian-Kun,Hou, Yi-Xuan,Liu, Dong
, p. 6778 - 6786 (2017)
Two photoreactive coordination polymers {[Zn(μ-OH2)(5-Me-1,3-bdc)(2,3′-bpe)]·H2O}n (1) and {[Ag2(5-Me-1,3-Hbdc)(2,3′-bpe)2][Ag(5-Me-1,3-bdc)(2,3′-bpe)]·H2O}n (3) have been prepar
Recyclable CoFe2O4–Ag2O magnetic photocatalyst and its visible light-driven photocatalytic performance
Zeng, Qihui,Zhu, Yingming,Tian, Wen,Jiang, Wei,Liang, Bin
, p. 4487 - 4502 (2017)
A magnetically separable photocatalyst, the composite compound CoFe2O4–Ag2O, was fabricated successfully by a simple precipitation method and used for photodegradation of organic pollutants under visible light (>420?nm) irradiation. Its magnetic separation performance was evaluated. Results showed that the CoFe2O4–Ag2O with 60-wt% content of Ag2O had the best photocatalytic performance, stability, and magnetic separation performance. Methyl orange, methylene blue, rhodamine B, and phenol can be completely photodegraded by the CoFe2O4–Ag2O photocatalyst in a short period. After five cycles, CoFe2O4–Ag2O kept its performance stability. As prepared, CoFe2O4–Ag2O (60%) has a coercivity of 2500 Oe and a saturation magnetization of 22.45?emu?g?1; it can be completely separated magnetically in 20?s with magnetic recovery mass rate of 85% under an external magnetic field. This superb photocatalytic performance and separation recovery confirms that the CoFe2O4–Ag2O photocatalyst is a promising candidate for future use in photo-oxidative degradation of organic contaminants.
Direct synthesis of AgInO2
Shahriari, Dean Y.,Erdman, Natasha,Haug, Ulrika T.M.,Zarzyczny, Matthew C.,Marks, Lawrence D.,Poeppelmeier, Kenneth R.
, p. 1437 - 1441 (2003)
Potential applications as transparent conducting oxides have made the study of ternary metal oxides based on the delafossite structure very attractive. The well known and understood thermal instability of noble metal oxides, and therefore the associated problems with high-temperature solid-state techniques to yield pure complex oxides based on noble metals, clearly illustrates the need for low-temperature alternatives. For the first time, synthesis of 3R-AgInO2 at low temperature (175 °C) and pressure (a single-step hydrothermal technique. Particle size of the orange crystallites ranged from 3 to 7 μm.
Performance promotion of Ag2O photocatalyst by particle size and crystal surface regulation
Fu, Hongyan,He, Jian,Jiang, Wei,Lin, Zehao,Wu, Pan,Zeng, Ya
, p. 10719 - 10728 (2020)
The insufficient photocatalytic performance of Ag2O makes it difficult to apply to actual industrial printing and dyeing waste water treatment systems, which contain a variety of organic pollutants. Therefore, it is urgent to improve the photocatalytic performance of Ag2O. In this study, the main factors affecting the properties of Ag2O photocatalysts were screened out by single factor experiments. Then, the optimum conditions for the preparation of Ag2O were simulated by response surface design. The prepared Ag2O showed good photodegradation performance to methyl orange and phenol, but the degradation of rhodamine B was significantly delayed. After that, the pyridine was introduced to adjust the crystal plane structure of Ag2O. The results showed that the photocatalytic oxidation capacity of Ag2O was greatly improved. Ninety percent of rhodamine was removed within 25 minutes. Moreover, the mechanism of controlling the photocatalytic performance has also been studied through fine characterizations.
Preparation of POSS-poly(ε-caprolactone)-β-cyclodextrin/Fe3O4hybrid magnetic micelles for removal of bisphenol A from water
Yuan, Weizhong,Shen, Jin,Li, Lulin,Liu, Xu,Zou, Hui
, p. 353 - 361 (2014)
A novel amphiphilic star-shaped inorganic-organic hybrid copolymer polyhedral oligomeric silsesquioxane-poly(ε-caprolactone)-β-cyclodextrin (POSS-PCL-β-CD) was synthesized by ring-opening polymerization (ROP) and click chemistry. The amphiphilic copolymer can self-assemble into hybrid micelles with hydrophobic POSS-PCL chain encapsulating Fe3O4nanoparticles as the core and β-CD as the shell after mixing with Fe3O4nanoparticles in solvent and dialysis against water. The chemical structure of POSS-PCL-β-CD was characterized by 1H NMR and the morphology of the magnetic hybrid micelles was characterized by TEM and DLS. Due to the host-guest interaction of β-CD with bisphenol A (BPA), POSS-PCL-β-CD/Fe3O4hybrid micelles present good adsorption capacity in removal of BPA from aqueous solution. Magnetic measurement reveals that POSS-PCL-β-CD/Fe3O4hybrid micelles still exhibit magnetism for separation by an external magnetic field, indicating that these magnetic hybrid micelles may have potential application in the field of environmental protection.
Operando Synthesis of a Dendritic and Well-Crystallized Molybdenum Oxide/Silver Catalyst for Enhanced Activity in the Hydrogen Evolution Reaction
Xia, Xiaohong,Shen, Xuan,Zhao, Xiaojuan,Ye, Weichun,Wang, Chunming
, p. 2517 - 2525 (2015)
Dendritic MoO3/Ag with good crystallinity has been prepared through an operando method. In the hydrogen evolution reaction (HER), this catalyst, which was designed to utilize the best properties of each component material, showed a high catalytic activity. After the precursor was drop-cast onto a glassy carbon electrode, a reductive potential was applied to the coated electrode, and H2 evolution occurred within the range of potentials. The overpotential required to evolve H2 at the benchmark rate decreased progressively with subsequent voltammetric cycles, until a steady state was reached at which only 145 mV of overpotential was required to pass -10 mAcm-2 of current density. During the electrocatalysis, the precursor was converted to catalyst through an operando method. This operando-synthesized MoO3/Ag catalyst has a low Tafel slope (43 mVdec-1), low overpotential (145 mV), and excellent durability for HER. It has the potential to be a promising material for HER. Operando star: A dendritic MoO3/Ag composite with good crystallinity is prepared through an operando method and it exhibited excellent catalytic properties in the hydrogen evolution reaction.
