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Biofuel cells

Biofuel cells. Arkady A. Karyakin. Faculty of Chemistry, M.V. Lomonosov Moscow State University, Moscow, Russia. Hydrogen-oxygen fuel cell. Bioelectrocatalysis. is an acceleration of electrode reactions by biological catalysts. Whole cells. Enzymes. Biofuel cells. Enzyme electrodes.

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Biofuel cells

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  1. Biofuel cells Arkady A. Karyakin Faculty of Chemistry, M.V. Lomonosov Moscow State University, Moscow, Russia

  2. Hydrogen-oxygen fuel cell

  3. Bioelectrocatalysis is an acceleration of electrode reactions by biological catalysts Whole cells Enzymes

  4. Biofuel cells Enzyme electrodes Intact cell based

  5. Thermodynamics of cathode reactions H2O2/H2O 1.85 V O2/H2O 1.2 V E, NHE O2/H2O2 0.6 V

  6. Intact cell based fuel cells • produce oxidizable compounds; • wired to the anode via mediators; • direct bioelectrocatalysis.

  7. Fuel cells based on bacteria producing oxidizable compounds • separated compartment of bioreactor and fuel cell; • same anode compartment.

  8. Oxidizable compounds: H2 – Clostridium, E. coli, Rhodobacter (phototrophic)etc. H2S, S – Desulfomicrobium Formate – Clostridium butiricum

  9. Fuel cells based on intact cells wired with diffusion free mediators substrate product • hexacyanoferate • azines • thionine • safranine • neutral red • azur A • indophenol • quinones • 1,4-naphthoquinone • 1,4-benzoquinone electrode medox medred cell wall respiratory membrane

  10. Microbial fuel cells based on direct bioelectrocatalysis Gil, G. C.; Chang, I. S.; Kim, B. H.; Kim, M.; Jang, J. K.; Park, H. S.; Kim, H. J. Biosensors & Bioelectronics2003, 18, 327-334.

  11. Electroactivity of Shewanellaputrefaciens A – air exposed cells B – air exposed with lactate C – no air, but at + 200 mV D – at +200 mV with lactate Kim, B. H.; Ikeda, T.; Park, H. S.; Kim, H. J.; Hyun, M. S.; Kano, K.; Takagi, K.; Tatsumi, H. Biotechnology Techniques1999, 13, 475-478.

  12. Acetate enriched consortium on graphite electrode Lee, J. Y.; Phung, N. T.; Chang, I. S.; Kim, B. H.; Sung, H. C. Fems Microbiology Letters2003, 223, 185-191.

  13. Current response of Desulfobulbuspropionicus Holmes, D. E.; Bond, D. R.; Lovley, D. R. Applied And Environmental Microbiology2004, 70, 1234-1237.

  14. Enzyme based fuel cells

  15. How to involve enzymes in bioelectrocatalysis? Use of mediators: Direct bioelectrocatalysis:

  16. Wired glucose oxidase B.A. Gregg, A. Heller. Anal. Chem. 62 (1990) 258

  17. Wiring of glucose oxidase E = -0.195 mV (Ag|AgCl) Heller, A. Physical Chemistry Chemical Physics2004, 6, 209-216.

  18. Wired bilirubin oxidase E = 0.35 V (Ag|AgCl) Heller, A. Physical Chemistry Chemical Physics2004, 6, 209-216.

  19. Actual characteristics of small batteries Heller, A. Analytical And Bioanalytical Chemistry2006, 385, 469-473.

  20. Hydrogen-oxygen energy sources

  21. Problems with Pt-based electrodes • Cost and availability; • Poisoning with CO, H2S etc.; • Low selectivity.

  22. 50 kW (<$ 10 000) Fuel cell cost problems 1 kW $ 200 - 2000 $ 10 000- $ 100 000

  23. Dinamics ofPt cost

  24. Available amount of Pt Annual production: 180 tonnes Assured resources: 100 000 tonnes every year: >60 · 106 cars 2 g of Pt per kW 50 kW engines > 6 000 tonnes Pt

  25. Short circuit Poisoning by fuel impurities Reforming gas (H2): 12.5 % of CO • under 0.1% CO activity irreversibly decreases 100 times after 10 min; • inactivation by H2S is 100 times more efficient. Pt electrodes: Solution: increase of potential

  26. Decreasedefficiency of energy conversion from 90% to 40-60% Low selectivity problems Pt – catalyst of both H2 oxidation and O2 reduction Contamination of electrode space

  27. BIOELECTROCATALYSIS P2 S2

  28. Direct bioelectrocatalysis Est = 1.2 V Berezin I. V., Bogdanovskaya V. A., Varfolomeev S.D., M.R. Tarasevich, A.I Yaropolov. Dokl.Akad.Nauk SSSR(Proc. Acad. Sci.) 240 (1978) 615-618

  29. Direct bioelectrocatalysis Equilibrium H+/H2 potential A.I. Yaropolov, A.A. Karyakin, S.D. Varfolomeyev, I.V. Berezin. Bioelectrochem. Bioenerg. 12 (1984) 267-77

  30. H2 (1), Ar (2) and CFM blank electrode (3) Hydrogenase electrodes on carbon filament tissue

  31. How to involve hydrogenases in bioelectrocatalysis? • sorption (surface choice & pretreatment); • promotion by polyviologens; • surface design by conducting polymers.

  32. Direct bioelectrocatalysis

  33. Effect of promoter

  34. Surface design by conductive polymers

  35. H2 (1) and Ar (2), sweep rate 2 mV/s Hydrogenase electrodes (a) adsorption

  36. Hydrogen fuel electrodes

  37. Bioelectrocatalysis – surface modification Hydrogenase from Thiocapsa roseopersicina

  38. Different hydrogenases in bioelectrocatalysis

  39. Current-voltage curves

  40. Kinetics of hydrogenase electrodes

  41. Catalytic properties

  42. Dependence on H2 content Pt-vulcan, 1 M H2SO4 D. baculatum/ LSG+polypyr.-violog.

  43. Reforming gas (H2): 12.5 % of CO under 0.1% CO activity irreversibly decreases 100 times after 10 min Pt electrodes: Poisoning by fuel impurities Hydrogenase el-ds: -not sensitive up to 1% of CO; -reversibly restore activity after inhibition; - not sensitive to 5 mM Na2S.

  44. Tolerance to oxygen

  45. Stability of hydrogen enzyme electrode at 80° С

  46. Hydrogenase Laccase E/mV 800 1200 0 H2  2H+ + 2e- 0,5 -2 O2 + 4H+ + 4e- 2H2O /mA cm i -0.4 200 E /mV r E = 1.23 V E = 1.198 V Theoretical D D Hydrogen-oxygen biofuel cell

  47. Hybrid enzyme-microbial fuel cell a consumption of biogas (microbiological H2) with hydrogen enzyme electrodes

  48. Enzyme electrode consumes H2 from microbial media • – criogel PVA with microbial consortium • - polyperchlorvinyl with spores of C. pasterianum

  49. Enzyme electrode consumes H2 from microbial media • Hydrogenase-C.pasterianum electrode • – in cultural medium • - in H2 saturated solution

  50. CONCLUSIONS • Enzyme electrodes are advantageous: • a completely renewable source; • solve problems: • selectivity; • poisoning by fuel impurities; • activity in neutral solutions similar to Pt in sulfuric acid; • able to consume H2 directly from microbial media.

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