Ti mesh

Shao et al. [35] not only used a similar Ti mesh to the one presented by Scott s group but also used a Ti mesh as the cathode DL in a DMFC. The main difference between both meshes was that the one used on the cathode side was coated on both sides with carbon black (Vulcan XC-72) and PTFE (i.e., with MPLs on each side). It was shown that this novel cathode DL performed similarly to conventional CFP DLs under comparable conditions. Chetty and Scott [36] also used a catalyzed Ti mesh as the anode DL, but in a direct ethanol fuel cell (DEFC) it performed better compared to a cell with a standard DL (CFP). 

ITottinen et al. [44,45] used htanium sintered meshes as DEs on the cathode side of a PEMEC because the porosity of these metal sheets does not reduce when in compression. It was demonstrated that in order ter the cell to achieve the required performance, the sintered meshes had to be coated with platinum. However, the results showed that a cell with CEP (SIGRACET GDEIO-BB) as the DE shll performed slightly better (especially at high current densities) than the cell with the Pt-coated sintered Ti mesh. Cisar et al. [46 presented another example in which a DE consisting of sintered metal fibers was used on the cathode side of a PEMEC. Once put together, these fibers were rmified or bonded to the EE plate (made out of metal) in order to combine the two components into one. 

C. Lim, K. Scott, R. G. Allen, and S. Roy. Direct methanol fuel cells using thermally catalyzed Ti mesh. Journal of Applied Electrochemistry 34 (2004) 929-933. 

Figure 13.7 shows typical linear sweep voltammograms (LSV) obtained using a Ti mesh-supported Pd cathode in 0.05 M sodium sulphate solutions with or without pentachlorophenol (PCP) and 2,4-dichlorophenol (DCP). 

Fig. 13.7 Linear sweep voltammograms for electrochemical HDH of pentachlorophenol (PCP) and 2,4-dichlorophenol (DCP) on a Ti mesh-supported Pd cathode (2mgPdcm-2, 4cm2). Cell H-cell divided by a Nation 117 membrane. Anode Pt mesh (lOcm2). Catholyte 0.05MNa2S04 (pH 3) solution without (blank) or with saturated PCP and DCP. Anolyte 0.05 M Na2S04 (pH 3) solution. Scan rate 5 mV s-1. Temperature 21.5 0.5°C...

The electrochemical HDH is much more effective than a chemical HDH, as compared in Fig. 13.8. In chemical HDH the same reactor with a Ti mesh-supported Pd catalyst was used. The PR for the HDH of PCP using a poor Ni cathode was even higher than that achieved in the chemical HDH, e.g. 20% against 15% at 120 min (Cheng et al. 2003a). 

Fig. 13.8 Change in the percentage of pentachlorophenol (PCP) removal for the electrochemical HDH of saturated aqueous solution using a Nation 117 membrane reactor. Active area 20 cm2. Cathode Pd or Pt/Ti mesh (2 mg Pd or Ptcm-2), Fe or Ni mesh. Anode Pt/Ti mesh (2mgPtcm-2). Anolyte Water. Flow rate 100ml min-1. Applied current density 10mAcm-2. Temperature 17 0.5°C...

Fig. 13.10 Change in space-time yield during the electrochemical HDH of 200 mM DBP in paraffin oil media using a Nation 117 membrane reactor. Ratios of the waste volume (cm3) to the cathode geometric surface area (cm2) are indicated in figure. Cathode Three-layer Ti mesh-supported Pd (25 cm2, 2 mg Pd cm-2). Anode Three-layer Ti mesh-supported Pt (25cm2, 2mgPtcm 2). Controlled current density 10 mAcm-2. Catholyte 200 mM DBP in paraffin oil (50-1,000cm3). Anolyte O.5MH2SO4 aqueous solution (50-1,000cm3). Flow rate 100 ml min-1. Temperature 18.5 0.5°C...

To be used in a realistic process, the HDH reactor should provide long-term operation. Figure 13.13 shows data for 250 h continuous operation for the HDH of 150 mM DBP in paraffin oil (l,000cm3) using a Nation 117 membrane with Ti mesh-supported Pd cathode and Pt anode, at a current density of 10mAcm 2. An anolyte of 0.5MH2SO4 aqueous solution (1,000 cm3) was used. 

Xie, Y. -B. and Li, X. -Z. (2006b) Interactive oxidation of photoelectrocatalysis and electro-Fenton for azo dye degradation using Ti02-Ti mesh and reticulated vitreous carbon electrodes. Mater. Chem. Phys. 95,39-50. 

Ti mesh in ovsirlsy AH Lticreajs 20+ Durable established Kystem, Main problem i.s overlay application... 

Yu EH, Scott K, Reeve RW, Yang LX, Allen RG (2004) Characterisation of platinised Ti mesh electrodes using electrochemical methods methanol oxidation in sodium hydroxide solutions. Electrochim Acta 49(15) 2443-2452... 

Yang KS, Mull G, Moulijn JA (2007) Electrochemical generation of hydrogen peroxide using surface area-enhanced Ti-mesh electrodes. Electrochim Acta 52 6304-6309... 

All powder samples for XRD analysis and morphology investigations were electrodeposited at the room temperature in the cylindrical glass cell of the total volume of 1 dm with cone-shaped bottom of the cell to collect powder particles in it. Working electrode was a glassy carbon rod of the diameter of 5 mm, with the total surface area of 7.5 cm immersed in the solution and placed in the middle of the cell. Cylindrical Pt-Ti mesh placed close to the cell... 

Figure 4.63. Comparison of methanol electrooxidation superficial current density for PtRu supported on RVC, UGF, and Ti mesh. 1 M CH3OH - 0.5 M H2SO4, 298 K, scan rate 5 mV s [218]. (With kind permission from Springer Science+Business Media Journal of Applied Electrochemistry, Direct methanol fuel cells with reticulated vitreous carbon, uncompressed graphite felt and Ti mesh anodes, 38, 2008, 51-62, Cheng T, Gyenge E, figure 7.)...

In addition to carbon and graphite-based extended reaction zone supports, Ti mesh has been fairly extensively investigated for direct methanol fuel cells in both acid and alkaline conditions, and also for formic acid cells [218, 305-307, 309-313]. Compared to three-dimensional carbons, Ti mesh has the advantage of a... 

In an alkaline (1 M NaOH) DMFC, on the other hand, where crossover to the cathode is alleviated, the Ti mesh-supported Pt outperformed the GDE in 1 M methanol over the entire investigated range of superficial current densities (up to 70 mA cm ) [311]. Thus, in the development and performance analysis of novel extended reaction zone supports, one must take into account the multitude of complex interactions involving support morphology, physico-chemical properties, electronic effects affecting the intrinsic electrocatalytic activity, and various mass transfer processes. 

In the case of a direct formic acid fuel cell equipped with Ti mesh anode support, Chetty and Scott carried out a comprehensive comparative investigation of Pd and PtSn catalysts prepared by either thermal or electrochemical deposition [309]. Generally, PtSn/Ti mesh performed better than Pd/Ti mesh the maximum power output for each at 333 K using 1 M HCOOH was about 20 mW cm and 37 mW cm, respectively. It is noteworthy that according to this study the Ti mesh-supported PtSn gave about three times higher peak power density than the GDE with commercial carbon supported PtSn [309]. Furthermore, the performance of the three-dimensional anode improved with formic acid concentration up to 7 M, and excellent catalyst stability was observed during 72 h of continuous operation. 

Cheng T, Gyenge E. Direct methanol fuel cells with reticulated vitreous carbon, uncompressed graphite felt and Ti mesh anodes. J Appl Electrochem 2008 38 51-62. 

Yu and Scott prepared membrane assembly electrodes (MEAs) with Pt loadings in both anode and cathode CLs of about 2 mg cm for a direct methanol alkaline fuel cell using an anion exchange membrane. They found that the cell performance increased dramatically with an MEA that did not include the GDL on the anode, because of lower reactant mass transfer resistance [94]. They also used platinized Ti mesh as the anode and current collector in the AEMFC. The cathode was a standard gas diffusion electrode with a Pt loading of approximately 2 mg cm , which consisted of a backing layer (carbon paper), a GDL and a CL. The novel anode showed higher catalytie aetivity than the conventional Pt/C electrode, and gave stable fuel cell performance [95]. 

Pt-Ti02 (Degussa P25) Carbon cloth Dropping and baking Pt/Ti mesh 1.0 M MeOH + 0.5 M H2 SO4 One-compartment cell Methanol 100 W Hg lamp and three 4 W UV tubes Liner a/. (2011)... 

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