ChemInform Abstract: Supported Catalysts. Deposition of Active Component: Impregnation and Ion Exchange

Che, M.; Clause, O.; Marcilly, C.

doi:10.1002/chin.200030258

Cited by 4 publications

(3 citation statements)

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“…Commonly used techniques include in situ photodeposition [27,28] and deposition of pre-prepared metal colloids [29,30]. Traditional way for preparing supported metal nanoparticles is impregnation with the appropriate metal salt followed by high temperature hydrogenation [31]. Calcination of the metal salt loaded on semiconductors by impregnation also resulted in effective cocatalysts for photocatalytic H 2 production [32].…”

Section: Introductionmentioning

confidence: 99%

PtOx-SnOx-TiO2 catalyst system for methanol photocatalytic reforming: Influence of cocatalysts on the hydrogen production

et al. 2018

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Abstract:Effects of modification of PtO x -TiO 2 photocatalysts by tin were elucidated by exploring relationships between the structural properties of variously prepared tin-loaded catalysts and their catalytic activity in methanol photocatalytic reforming. Tin free and amorphous tinoxide decorated TiO 2 samples were prepared by sol-gel method from titanium-isopropoxide.In other approach, Sn was loaded onto the sol-gel prepared TiO 2 by impregnation followed by calcination. Pt was introduced by impregnation followed by either reduction in H 2 at 400 o C or calcination at 300 o C. TEM, XRD and Raman spectroscopic measurements proved that TiO 2 existed in the form of aggregates of polycrystalline anatase with primary particle size of 15-20 nm in each of the samples. Photocatalytic hydrogen production was influenced by the combined effect of many parameters. Both the presence of Sn and the way of Pt co-catalyst formation played important role in the activity of these photocatalysts. The Sn introduction by both sol-gel method and impregnation clearly enhanced the photocatalytic activity.

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Section: Introductionmentioning

confidence: 99%

PtOx-SnOx-TiO2 catalyst system for methanol photocatalytic reforming: Influence of cocatalysts on the hydrogen production

et al. 2018

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“…However, this co-catalysts/semiconductor system is less effective in the methanol photocatalytic reforming reaction [31]. High temperature reduction of the metal precursor [32] in H 2 is one of the most commonly used methods to prepare supported metal catalysts, but it is believed unsuitable for oxynitrides because of their limited thermal stability compared to oxides [33].…”

Section: Introductionmentioning

confidence: 99%

Structural evolution in Pt/Ga-Zn-oxynitride catalysts for photocatalytic reforming of methanol

Vass

Pászti

Bálint

et al. 2016

Materials Research Bulletin

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Products of microwave-assisted urea-induced co-precipitation of Ga(NO 3 ) 3 and Zn(NO 3 ) 2 or Ga 2 O 3 and ZnO were nitridated in order to obtain Ga-Zn-based photocatalysts. Irrespectively to the starting material, wurtzite-like Ga-Zn-oxynitride phases formed. The preparation was completed by deposition of a Pt co-catalyst, which was activated by either reduction in hydrogen or calcination in air. It was demonstrated by X-ray diffraction (XRD), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS) that during oxidative activation the oxynitride started to transform into a nitrogen-free Zn-containing Gaoxyhydroxide. Regardless to the structure of the catalysts after the activation step, almost complete oxynitride to oxyhydroxide transformation was observed during the methanol photocatalytic reforming reaction, accompanied by complete reduction of the Pt co-catalyst to metallic state. The observations of this study point to the importance of phase transitions under reaction conditions in the development of the active ensemble in the Ga,Zn-based photocatalysts.

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“…2.3 g of powdered high surface area graphite (Brunauer-Emmett-Teller (BET) surface area 509 m 2 g -1 ) was dried at approximately 443 K under dynamic vacuum for 1.5 h to remove water from the pores. After cooling down to room temperature the fine carbon powder was (co-)impregnated to incipient wetness 277 , defined as 95% of the total pore volume by N2 physisorption, under static vacuum with a 0.1 M HNO3 solution containing 1.8 M copper (and 1.0 M zinc) nitrates. The impregnated support was subsequently dried at room temperature under dynamic vacuum overnight and reduced at 503 K (ramp 2 K min -1 ) in a 100 mL min -1 flow of 20 vol% H2/N2 for 2.5 h. To be able to store and handle the catalyst in the oxidized state, it was exposed to a flow of 100 mL min -1 of 5 vol% O2/N2 for 1 h, heated to 473 K with a ramp of 1 K min…”

Section: Catalyst Synthesismentioning

confidence: 99%

Copper Catalysts for Synthesis Gas Conversion - Promoter and Support Effects

Dalebout¹

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When someone has heard of a catalyst before, it has often been explained as a car part that cleans the exhaust gases. However, there are many more types of catalysts used in the industrial production of almost any chemical, ranging from enzymes (biocatalysis) for the production of medicines to solid catalysts for gasoline and plastics production. 1,2 A catalyst is in general a substance that is used to accelerate a chemical reaction from starting compound A to desired product B by lowering the activation barrier (figure 1.1A), while the substance itself is not consumed. 3 For example, inside the three-way catalytic converter in gasoline-type cars several catalyzed reactions simultaneously occur: hydrocarbons, carbon monoxide (CO), and nitrogen oxides (NOx) in the high exhaust stream are converted into the less harmful carbon dioxide (CO2), water (H2O), and nitrogen gas (N2). 4 Here, we focus on heterogeneous catalysts, which are solid catalysts used in liquid-or gas-phase reactions. The active compound in heterogeneous catalysts is often a metal (oxide or sulfide). Figure 1.1 (A) Energy diagram of a catalyzed and non-catalyzed chemical reaction with Eact representing the activation energy. (B) Transfer of electron density from the d-band of a metal to an anti-bonding orbital of a reactant (here σ* of an H2 molecule). Back-donation (as indicated by the arrow) induces bond breaking. Adapted from ref. [3]. (C) Different binding modes of a CO molecule on a metal surface. 493 60 2,000 b 12.4 50.7 42.6 6.3 [177] a N-C = ordered mesoporous nitrogen-doped carbon, KIT-6 = ordered mesoporous silica, last entry = physical mixture. b In mL gcat -1 h -1 . c C2+OH = higher alcohols, HC = hydrocarbons. d Without taking CO2 into account.

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ChemInform Abstract: Supported Catalysts. Deposition of Active Component: Impregnation and Ion Exchange

Cited by 4 publications

References 0 publications

PtOx-SnOx-TiO2 catalyst system for methanol photocatalytic reforming: Influence of cocatalysts on the hydrogen production

PtOx-SnOx-TiO2 catalyst system for methanol photocatalytic reforming: Influence of cocatalysts on the hydrogen production

Structural evolution in Pt/Ga-Zn-oxynitride catalysts for photocatalytic reforming of methanol

Copper Catalysts for Synthesis Gas Conversion - Promoter and Support Effects

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