Fabrication catalyst coating

In this study, we developed microchannel PrOx reactor to control CO outlet concentrations less than 10 ppm from methanol steam reformer for PEMFC applications. The reactor was developed based on our previous studies on methanol steam reformer [5] and the basic technologies on microchaimel reactor including design of microchaimel plate, fabrication process and catalyst coating method were applied to the present PrOx reactor. The fabricated PrOx reactor was tested and evaluated on its CO removal performance. 

Ness S.R., Dunham G.E., Weber G.F. and Ludlow D.K., SCR catalyst-coated fabric filters for simultaneous NO and high-temperature particulate control, Environmental Progress 14 69 (1995). 

Define pilot manufacturing scale-up of the processes for fabrication of catalysts, catalyst coated membrane (CCM) assemblies, and electrode backing media. 

Phase 2 Laboratory-scale catalyst-coated membranes (CCMs) will be fabricated, optimized and tested using the Phase 1 down-selected membranes and catalysts. 

In the preparation of MEA, there are two options. One is to coat the CL onto the DM such as carbon paper, or carbon cloth, the other is to coat the CL onto the PEM, as shown in Figure 3.17. The CL coated on the diffusion medium is called Catalyst-coated Diffusion Medium (CDM), and the CL coated on the membrane is called Catalyst Coated Membrane (CCM). Using a hot-press process, by sandwiching PEM between two CDMs, or CCM between two DMs, an MEA can be fabricated for fuel cell testing. 

The liquid-junction semiconductor electrodes stabilized by polymer-coating can be used for photochemical conversion systems. The stabilized n-CdS coated with PP which incorporates RUO2 as catalyst was used for visible-light-induced water cleavage Photochemical diodes were fabricated by coating CdS with PP and polystyrene films, the latter containing metal dispersions such as Pt, Rh and RUO2 as a catalyst (Fig. 35). 

Once the ceramic monolith is fabricated and coated with catalyst, it needs to be canned in a metallic reactor body. A mat material is used to bridge the gap between... 

To date, there are two major types of catalyst layer fabrication techniques. One is to cast or spray the catalyst ink onto the gas diffusion layer to form a catalyzed GDL (CGDL), which is hydrophobic and has a thickness of about 20-50 pm the other is to deposit or spray catalyst ink onto the proton exchange membrane to form a catalyst coated membrane (CCM), a hydrophilic layer with a thickness of 5-10 pm. 

The phosphoric acid-doped neat-PBI and PBI/PTFE PEMs were used to prepare MEAs, and high-temperature fuel cell tests were conducted using the prepared MEAs. Most of the GDEs were fabricated by coating a Pt-C/ PBI/DMAc ([PBI]/[PBI -I- Pt-C] = -5-10 wt %) catalyst solution on a carbon paper and drying it at 120-150 °C under vacuum to evaporate DMAc. The GDE was then doped with 85 wt% phosphoric acid. The phosphoric acid-doped PEM was sandwiched in between the two phosphoric acid-doped GDEs and then pressed to obtain the MEA. The detailed procedures of GDE fabrication and MEA preparation can be obtained in literature [49, 53-60]. 

Early MEA fabrication relied on catalyst deposition directly onto the GDL materials (via spraying, screen printing, or blade application), and subsequent bonding to the membrane. Other MEA designs incorporate mass-produced, catalyst-coated membranes (CCMs) that are separated from the GDL by one or more sublayers. These sublayers can be fabricated from multiwalled carbon nanotubes (Kannan et al, 2009), doped polyaniline (PANl) (Cindrella and Kannan, 2009), or more commonly, carbonaceous particles with polymeric binders. The pore diameters in the resulting MPL can be two orders of magnitude smaller than the corresponding pores in the GDL (e.g., 10 m and 10 m, respectively). 

Catalyst coating is another important process in fabricating micro fuel cells. Uniform and reliable catalyst coating is extremely crucial for mini type fuel cells. The preparation method and compatibility between catalyst and substrate affect the activity and durability of the catalyst layer. 

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