600 likes | 1.02k Views
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. Enzyme electrodes. Intact cell based.
E N D
Biofuel cells Arkady A. Karyakin Faculty of Chemistry, M.V. Lomonosov Moscow State University, Moscow, Russia
Bioelectrocatalysis is an acceleration of electrode reactions by biological catalysts Whole cells Enzymes
Enzyme electrodes Intact cell based Biofuel cells
E, NHE Thermodynamics of cathode reactions H2O2/H2O 1.85 V O2/H2O 1.2 V O2/H2O2 0.6 V
Intact cell based fuel cells • produce oxidizable compounds; • wired to the anode via mediators; • direct bioelectrocatalysis.
Fuel cells based on bacteria producing oxidizable compounds • separated compartment of bioreactor and fuel cell; • same anode compartment.
Oxidizable compounds: H2 – Clostridium, E. coli, Rhodobacter (phototrophic)etc. H2S, S – Desulfomicrobium Formate – Clostridium butiricum
electrode cell wall respiratory membrane 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 medox medred
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.
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.
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.
Current response of Desulfobulbuspropionicus Holmes, D. E.; Bond, D. R.; Lovley, D. R. Applied And Environmental Microbiology2004, 70, 1234-1237.
How to involve enzymes in bioelectrocatalysis? Use of mediators: Direct bioelectrocatalysis:
Wired glucose oxidase B.A. Gregg, A. Heller. Anal. Chem. 62 (1990) 258
Wiring of glucose oxidase E = -0.195 mV (Ag|AgCl) Heller, A. Physical Chemistry Chemical Physics2004, 6, 209-216.
Wired bilirubin oxidase E = 0.35 V (Ag|AgCl) Heller, A. Physical Chemistry Chemical Physics2004, 6, 209-216.
Actual characteristics of small batteries Heller, A. Analytical And Bioanalytical Chemistry2006, 385, 469-473.
Problems with Pt-based electrodes • Cost and availability; • Poisoning with CO, H2S etc.; • Low selectivity.
50 kW (<$ 10 000) Fuel cell cost problems 1 kW $ 200 - 2000 $ 10 000- $ 100 000
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
Short circuit Poisoning by fuel impurities Reforming gas (H2): 12.5 % 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
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
BIOELECTROCATALYSIS P2 S2
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
Direct bioelectrocatalysis Equilibrium H+/H2 potential A.I. Yaropolov, A.A. Karyakin, S.D. Varfolomeyev, I.V. Berezin. Bioelectrochem. Bioenerg. 12 (1984) 267-77
H2 (1), Ar (2) and CFM blank electrode (3) Hydrogenase electrodes on carbon filament tissue
How to involve hydrogenases in bioelectrocatalysis? • sorption (surface choice & pretreatment); • promotion by polyviologens; • surface design by conducting polymers.
H2 (1) and Ar (2), sweep rate 2 mV/s Hydrogenase electrodes adsorption
Bioelectrocatalysis – surface modification Hydrogenase from Thiocapsa roseopersicina
Dependence on H2 content Pt-vulcan, 1 M H2SO4 D. baculatum/ LSG+polypyr.-violog.
Reforming gas (H2): 12.5 % 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.
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
Hybrid enzyme-microbial fuel cell a consumption of biogas (microbiological H2) with hydrogen enzyme electrodes
Enzyme electrode consumes H2 from microbial media • – criogel PVA with microbial consortium • - polyperchlorvinyl with spores of C. pasterianum