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Low Temp CO2RR - Coggle Diagram

- - - - Metallic over SnO2, since SnO2 shows lower catalytic activity in literature. SnO2 appears to preserve selectivity at higher current density though; could be a voltage question, fundamentally.
      - Calcination limited to well below 232C, to avoid melting, or particle growth.
    - - Hazardous to handles, meant for pH 7-9 operation (best with HCO3- ion)
  - - - Bi2O3, should be dominant specie in high alkalinity. Shown to be active specie in literature.
      - For Bi2O3 on Cu, calcination as low as 145C shown to turn Cu to CuO. Will need to be done in inert environment. https://aip.scitation.org/doi/pdf/10.1063/1.4995173
  - - - More hydrophillic
    - - More hydrophobic
        
        Seems relevant to gas phase electrodes, push water off, so it prefers the membrane. Prevent formation of water layer at site, slowing CO2 diffusion.
    - - Dioxide Materials literature showed performance in the following order of wt%, 4>8>16>1>32. Appears it could be optimized beyond that, on some side of 4. Seems likely it's less than 4. Other literature using Nafion used a loading of 3.45%.
        
        4%
        
        3.5%
  - - - Hard to track down which was used, went with 60% suspension from Sigma Aldrich
      - Daikin D210C is designed as battery binder, could be a good fit, if they ever respond
      - Sustainion ionomers used with PTFE, not independently
  - - - If it is to be used on the anode, voltage needs to be limited, which means current needs to be limited through 36mA.
      - Alternative is Titanium screen/mesh/felt. For long term use Ti needs to be platinum coated; preventing TiO2 passivation, which drives up the voltage.
- - - - by the hour, $50-200. Could be 4-5 samples per hour
      - Need an a candidate for standard specie
        
        Thiol? Amine? larger molecule than Glycerol?
      - Need to produce a standards solution, for calibration purposes. Should include all species of interest.
      - May be best method for Cathode and flush streams. Where relatively uncomplicated species mix expected.
  - - - They aren't set up for these compounds
- - - - Available in PAN precursor, available activated, lowest ohmic resistance
    - - Available in PAN precursor, available activated
        
        Flow frame available from Scribner
    - - Greatest surface for catalysis
        
        Greatest non catalytic surface. No longer produced due to perpendicular resistivity.
  - - - Better mixing, higher pressure drop, may be harder on catalyst adhesion, better use of catalyst and membrane area
    - - Classic design, referable in literature
  - - - Appears to promote leak, hard to place, spends more membrane
    - - Attempt rastered gaskets
- - - - Organic carrier fluid selected for better wetability of graphite
        
        Selection for least polar and lowest viscosity
        
        Acetone
        
        Toluene
        
        THF
      - Follow Lit suggesting 1/2 each isopropyl and UPDI
    - - Concern that entire support would be covered
        
        Support may be critical to CO2 adsorption. Covering support entirely, as could be expected in plating, could compromise functionality of the catalyst+support combination. Also prevents the possible functionalization of the support to further enhance CO2 adsorption.
      - Plating will not necessarily infiltrate all the way through
        
        Faraday Technologies showed that pretreating the GDL with ionomer can offer plated Sn Particles that are both well associated with ionomer and carbon CC, leading to massive improvements in performance (150 to 388 mA/cm^2, both at 150nm Sn sizing, 80% selectivity). http://www.faradaytechnology.com/PDF%20files/Publications/MRS%202016%20-%20Pulsed%20Electrodeposition%20of%20Tin%20Electrocatalysts%20for%20CO2%20Reduction%20to%20Formate.pdf
  - - - Graphite
        
        Scant literature on pyrolytic graphite alone. Mostly about composites. Absorbs significant energy before vaporizing, needed more than a 75W CO2 laser (we have a 60W). Some success with 0.1mm thick sample at 60W. We have 3.175 sheet and 6mm felt.
      - Flow frames
        
        UHMWPE
        
        Polypropylene
        
        Teflon
        
        Technically feasible but pay attention to gas effluent
    - - Felt
        
        Paper Guillotine
        
        Guard is too low to allow samples through
        
        Utility blade
      - Sheet
        
        Utility blade followed by chisel
        
        Utility blade alone creates raised lip, inappropriate for cross section view under scope. Raised lip will also encourage pooling of carrier fluid during deposition, even if it isn't present during microscopy step.
- - - - Known to spring leaks. Especially at o-rings
    - - Will stop leaks in context of compressible gaskets
    - - Will stop leaks in context of incompressible gaskets
        
        Incompressible gaskets appear to be glass and fluoridated polymer based. Not compatible with 60W laser. Also this torque exceeds our wrench output.
- - - - Will it be worse with gas flow in the cathode?
      - How can we measure this?
      - How can we control for this?
  - - - At minimum pump rate ("1", 0.066 ml/min) and 4 mmol K2CO3 (pH 8.98), full conversion (Gly basis, 0.11825 mmol Gly) requires 20.08 mAh/cm^2. (Current stoichiometry.xlsx)
- - - - Apply a vigorous purge at first, clearing the cell necks. Use bent steel tubing for this. Run an open syringe needle for purge flush, occasionally tap it with GC syringe for time point.
      - Control run: K2CO3/KCl soln. Sn vs Au/Pt (known OER cat). Run 2V, 2 hr. Collect samples intermittently. Record current.
      - Test run: K2CO3/KCl 1M Gly. Sn vs Bi2O3. Run 2V. Collect samples intermittently. Record current.