Non-carbon supports

Some non-carbon supports are also electrochemically unstable. For example, when TIC was used as a catalyst support to form Pt/TiC and PtsPd/TiC ORR catalysts, its electrooxidation at potential higher than 0.8 V vs RHE was found. When TiC Ti02 core—shell composite was used for the support, the electrochemical stabilities were significantly improved. 

Other non-carbon supports such as TiN, WC, and TiC have also been explored as the Pt catalyst supports to form Pt or Pt-alloy catalysts in the effort to improve the support s electric conductivity and durability. For example, tungsten carbide (WC) appears to be attractive. The experiment results showed that WC showed a high stability and good electronic conductivity. 

Wang, Y.-J., Wilkinson, D.P, and Zhang, J. (2011) Non-carbon support materials for polymer electrolyte membrane fuel cells. Chem. Rev., Ill, 7625-7651. 

To date, there have been two notable approaches (1) highly graphitic sp -like support materials (often with a microstructure very much different than Vulcan/ TKK) that include the synthesis of adatom (N, S, B, and P)-functionalized carbons and (2) non-carbon support materials, which are typically electrically conductive... 

Tungsten-based materials as n-type semiconductor with nonstoichiometric compositions are extremely stable under electrochemical oxidation conditions and could be used as a non-carbon support for catalyst. The interest in their use as catalyst support is due to the possible synergetic effect between metal catalyst and support. 

In terms of improving the catalyst activity, the main research focus is on Pt alloys and non-carbon support catalysts, which show promising results especially towards the ORR. 

Recently, rhodium and ruthenium-based carbon-supported sulfide electrocatalysts were synthesized by different established methods and evaluated as ODP cathodic catalysts in a chlorine-saturated hydrochloric acid environment with respect to both economic and industrial considerations [46]. In particular, patented E-TEK methods as well as a non-aqueous method were used to produce binary RhjcSy and Ru Sy in addition, some of the more popular Mo, Co, Rh, and Redoped RuxSy catalysts for acid electrolyte fuel cell ORR applications were also prepared. The roles of both crystallinity and morphology of the electrocatalysts were investigated. Their activity for ORR was compared to state-of-the-art Pt/C and Rh/C systems. The Rh Sy/C, CojcRuyS /C, and Ru Sy/C materials synthesized by the E-TEK methods exhibited appreciable stability and activity for ORR under these conditions. The Ru-based materials showed good depolarizing behavior. Considering that ruthenium is about seven times less expensive than rhodium, these Ru-based electrocatalysts may prove to be a viable low-cost alternative to Rh Sy systems for the ODC HCl electrolysis industry. 

As shown in chapter 6.5., the environment is only alkaline in the non-carbonated masonry. It was also established that an alkaline environment even supports the accumulation of cyanide and certain other steps in the reaction towards the formation of Iron Blue. If one assumes, as an extreme case, a complete conversion of all iron compounds contained in the masonry into pigment (1 to 2% iron content), the values found by Leuchter are even rather low. Whether the walls of the disinfestation wing were painted blue, i.e., whether a high cyanide content can only be found on the upper, i.e., the paint layer of the wall, will be discussed at a later time. 

Alkaline. Fuels are hydrogen and oxygen in a concentrated solution of potassium hydroxide at room temperature. The possible advantage is the use of non-platinum catalysts such as Raney nickel and silver on carbon supports. This is at an earlier stage of development than the other cells. 

The SPE HDH reactor is flexible in terms of structural materials and functions, e.g. electrode materials could be mesh- or carbon-supported gas diffusion ones the SPE could be a cation or anion exchange membrane (e.g. Nafion 117 or Fu-MATech FT-FKE-S) and the reactor can treat either aqueous or non-aqueous (e.g. a paraffin oil) wastes with or without supporting electrolytes. 

The anode and cathode electrodes currently consist of Pt or Pt alloys on a carbon support. Two low-cost, nonprecious metal alternative materials for anode catalysts are WC and WO. Pt alloyed with W, Sn, or Mo has also been evaluated for anode catalyst materials. Some non-Pt cathode catalysts that are being evaluated include TaOo.92> Nj osZrO, pyrolyzed metal porphyrins such as Ee- or Co-NJC and... 

Bezerra et al extensively reviewed heat treatment and stability effects of various Pt/C, Pt-M/C, and C-supported Pt-free alloy catalysts, taking into account particle sizes and stiuctural parameters. Appropriate heat treatment of Pt/C catalysts improves ORR activity by stabilizing the carbon support against corrosion, which in turn increases the cathode life time. Depositing mixed-metal Pt monolayers on carbon-supported metal nanoparticles or Pt monolayers on noble/non-noble core-shell nanoparticles leads to enhanced electrode performance. RRDE experiments on the catalytic activity of Pt-M (M = Au, Pd, Rh, Ir, Re or Os) monolayers on carbon-supported Pd nanoparticles showed that an 80 20 PtiM ratio for the nuxed monolayers performs better than commonly nsed Pt/C catalysts. ... 

Non-polar supports like polystyrene/divinylbenzene copolymers or carbon are also used as column materials. Alumina is polar and acidic while TiOi, and zirconia are much more neutral. They all have good aqueous stability compared to silica. Normal phase chromatography is restricted to the separation of stereochemical isomers, diastereomers, low molecular weight aromatic compounds and functionalized long chain aliphatic compounds. 

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