- Email: [email protected]
Supported methanol oxidation catalyst by reverse micelles method
RESEARCH TRENDS
and method of its production’ (1999); US 6007934 ‘CO-tolerant anode catalyst for PEM fuel cells and a process for its preparation’ (1999); US 6066410 ‘Anode catalyst for fuel cells with polymer electrolyte membranes’ (2000); EP 1037295 ‘Method for applying electrode layers on a tape-like polymer electrolyte membrane for fuel cells’ (2000); and others. 5. S. Wieland, F. Baumann and K.A. Starz (2001) ‘New powerful catalysts for autothermal
Research Trends Inorganic modification of protonconductive polymer DMFC membranes New organic-inorganic composite membranes based on sulfonated polyetherketone (SPEK) and sulfonated poly(ether ether ketone) (SPEEK) were synthesized for DMFC applications, with water and methanol permeabilities reduced by inorganic modification. Modification with ZrO2 gave a 60-fold reduction in methanol flux, but with a 13-fold reduction in conductivity. Modification with organically modified silane gave a 40-fold decrease in water permeability without a large decrease in proton conductivity. A ZrO2/zirconium phosphate mixture gave a good balance of high conductivity and low water/methanol permeability, for a 28-fold water flux reduction with only 10–30% proton conductivity reduction. S.P. Nunes, B. Ruffmann, E. Rikowski, S. Vetter and K. Richau: J. of Membrane Science 203(1/2) 215–225 (30 June 2002).
Supported methanol oxidation catalyst by reverse micelles method Carbon-supported PtRu alloy catalyst was prepared by the reverse micelles method. Catalyst particles were homogeneously dispersed on carbon support with narrow particle size distribution. The PtRu/C catalyst prepared by the reverse micelles method exhibited a higher catalytic activity during methanol electrooxidation than the standard PtRu/C (E-Tek) catalyst. Y. Liu, X. Qiu, Z. Chen and W. Zhu: Electrochemistry Communications 4(7) 550–553 (July 2002).
PEMFC water management using magnetic particles in cathode catalyst Cathode flooding is a primary reason for poor cell performance. When magnetic particles are
12
Fuel Cells Bulletin
reforming of hydrocarbons and water-gas shift reaction for on-board hydrogen generation in automotive PEMFC applications’. SAE 2001 World Congress, March 2001, SAE Technical Paper Series SP-1589, Paper 2001-01-0234. For more information, contact: OM Group Inc, 50 Public Square, Suite 3500, Cleveland, OH 44113, USA. Tel: +1 216 781 0083, Fax: +1 216 781 1502, www.omgi.com
deposited in the cathode catalyst layer and magnetized, the cell performance is improved over the non-magnetized case. Numerical simulation shows that the magnetic particles’ repulsive Kelvin force manages water flow in the porous electrode; the water saturation level near the catalyst interface decreases with increasing residual magnetic flux density of the magnetic particle; and the magnetic particles improve cell performance by decreasing the saturation and making more pore space for oxygen, with cell performance of a PEM fuel cell improved in the current-limited region. L.B. Wang, N.I. Wakayama, and T. Okada: Electrochemistry Communications 4(7) 584–588 (July 2002).
Energy recovery for fuel reforming in PEMFC power plants This work reports an energy recovery system that recovers waste thermal energy from a fuel cell stack and uses it for fuel reforming. The power plant efficiency can be increased by more than 40% compared with that of a fuel cell power plant alone, and up to 90% of the waste heat generated in the stack is recovered. As a result, the required heat dissipation capacity of the radiator used for cooling the stack can be dramatically reduced. The results also indicate that the power plant performance is relatively insensitive to stack operating temperature and pressure. Y. Cao and Z. Guo: J. of Power Sources 109(2) 287–293 (1 July 2002).
PEMFC operation >100°C using silicon oxide composite membranes Perfluorosulfonic acid (PFSA) membranes were studied as pure and silicon oxide composite membranes for operation in PEM fuel cells at 80–140°C. Sol-gel preparation of polymeric silicon oxide and impregnation into extruded PFSAs or co-recasting with solubilized PFSAs produced a uniform, homogeneous distribution of silicon oxide. Lower resistivities were attained at elevated PEMFC temperatures by reducing the PFSA equivalent weight and thickness. The
Specific contacts: Sales Manager Europe: Markus Holzmann, Email: [email protected] Marketing & Sales Manager Asia: Dr Holger Dziallas, Email: [email protected] mgi.com Marketing & Sales USA: Rob Privette, Email: [email protected] R&D PEM fuel cells: Dr Gerhard Sextl, Email: [email protected] R&D SOFCs: Dr Martin Payne, Email: [email protected]
silicon oxide modified PFSAs demonstrated improved water management at elevated temperatures, making it possible for such PEMFCs to be operated at 130°C with desirable current densities. K.T. Adjemian, S. Srinivasan, J. Benziger and A.B. Bocarsly: J. of Power Sources 109(2) 356–364 (1 July 2002).
Simulating process settings for unslaved SOFC response A common approach to reliable loadfollowing is to ‘slave’ the fuel cell response to the reactants supply subsystem (e.g. fuel processor). A change-in-power demand may be time-sensitive, however, and slaving the fuel cell response to that of the slower balanceof-plant components may not be practical. This model simulates the unrestrained loadfollowing characteristics of the Siemens Westinghouse tubular SOFC. Analysis shows that initial conditions exist which facilitate timely responses to increases in load demand, among them lower fuel utilization, higher operating voltage and optimized cell potential reduction. C. Haynes: J. of Power Sources 109(2) 365–376 (1 July 2002).
Development of 10 kWe PROX system for FCVs A preferential oxidation (PROX) reactor for a 10 kWe automotive PEM fuel cell system has been developed. The reactor is designed as a dualstage, multi-tube system. The performance is evaluated by feeding simulated gasoline reformate containing 1.2 wt% CO. The CO concentration of the treated ref ormate is <20 ppm at steady state and <30 ppm at 65% load change. Hydrogen loss in the steady state is about 1.5%, and the pressure drop across the reactor is 4 psi (0.3 bar). At startup the system takes 3 min to reduce the CO concentration to <20 ppm, although several controllable factors could shorten this. S.H. Lee, J. Han and K.-Y. Lee: J. of Power Sources 109(2) 394–402 (1 July 2002).
October 2002
and method of its production’ (1999); US 6007934 ‘CO-tolerant anode catalyst for PEM fuel cells and a process for its preparation’ (1999); US 6066410 ‘Anode catalyst for fuel cells with polymer electrolyte membranes’ (2000); EP 1037295 ‘Method for applying electrode layers on a tape-like polymer electrolyte membrane for fuel cells’ (2000); and others. 5. S. Wieland, F. Baumann and K.A. Starz (2001) ‘New powerful catalysts for autothermal
Research Trends Inorganic modification of protonconductive polymer DMFC membranes New organic-inorganic composite membranes based on sulfonated polyetherketone (SPEK) and sulfonated poly(ether ether ketone) (SPEEK) were synthesized for DMFC applications, with water and methanol permeabilities reduced by inorganic modification. Modification with ZrO2 gave a 60-fold reduction in methanol flux, but with a 13-fold reduction in conductivity. Modification with organically modified silane gave a 40-fold decrease in water permeability without a large decrease in proton conductivity. A ZrO2/zirconium phosphate mixture gave a good balance of high conductivity and low water/methanol permeability, for a 28-fold water flux reduction with only 10–30% proton conductivity reduction. S.P. Nunes, B. Ruffmann, E. Rikowski, S. Vetter and K. Richau: J. of Membrane Science 203(1/2) 215–225 (30 June 2002).
Supported methanol oxidation catalyst by reverse micelles method Carbon-supported PtRu alloy catalyst was prepared by the reverse micelles method. Catalyst particles were homogeneously dispersed on carbon support with narrow particle size distribution. The PtRu/C catalyst prepared by the reverse micelles method exhibited a higher catalytic activity during methanol electrooxidation than the standard PtRu/C (E-Tek) catalyst. Y. Liu, X. Qiu, Z. Chen and W. Zhu: Electrochemistry Communications 4(7) 550–553 (July 2002).
PEMFC water management using magnetic particles in cathode catalyst Cathode flooding is a primary reason for poor cell performance. When magnetic particles are
12
Fuel Cells Bulletin
reforming of hydrocarbons and water-gas shift reaction for on-board hydrogen generation in automotive PEMFC applications’. SAE 2001 World Congress, March 2001, SAE Technical Paper Series SP-1589, Paper 2001-01-0234. For more information, contact: OM Group Inc, 50 Public Square, Suite 3500, Cleveland, OH 44113, USA. Tel: +1 216 781 0083, Fax: +1 216 781 1502, www.omgi.com
deposited in the cathode catalyst layer and magnetized, the cell performance is improved over the non-magnetized case. Numerical simulation shows that the magnetic particles’ repulsive Kelvin force manages water flow in the porous electrode; the water saturation level near the catalyst interface decreases with increasing residual magnetic flux density of the magnetic particle; and the magnetic particles improve cell performance by decreasing the saturation and making more pore space for oxygen, with cell performance of a PEM fuel cell improved in the current-limited region. L.B. Wang, N.I. Wakayama, and T. Okada: Electrochemistry Communications 4(7) 584–588 (July 2002).
Energy recovery for fuel reforming in PEMFC power plants This work reports an energy recovery system that recovers waste thermal energy from a fuel cell stack and uses it for fuel reforming. The power plant efficiency can be increased by more than 40% compared with that of a fuel cell power plant alone, and up to 90% of the waste heat generated in the stack is recovered. As a result, the required heat dissipation capacity of the radiator used for cooling the stack can be dramatically reduced. The results also indicate that the power plant performance is relatively insensitive to stack operating temperature and pressure. Y. Cao and Z. Guo: J. of Power Sources 109(2) 287–293 (1 July 2002).
PEMFC operation >100°C using silicon oxide composite membranes Perfluorosulfonic acid (PFSA) membranes were studied as pure and silicon oxide composite membranes for operation in PEM fuel cells at 80–140°C. Sol-gel preparation of polymeric silicon oxide and impregnation into extruded PFSAs or co-recasting with solubilized PFSAs produced a uniform, homogeneous distribution of silicon oxide. Lower resistivities were attained at elevated PEMFC temperatures by reducing the PFSA equivalent weight and thickness. The
Specific contacts: Sales Manager Europe: Markus Holzmann, Email: [email protected] Marketing & Sales Manager Asia: Dr Holger Dziallas, Email: [email protected] mgi.com Marketing & Sales USA: Rob Privette, Email: [email protected] R&D PEM fuel cells: Dr Gerhard Sextl, Email: [email protected] R&D SOFCs: Dr Martin Payne, Email: [email protected]
silicon oxide modified PFSAs demonstrated improved water management at elevated temperatures, making it possible for such PEMFCs to be operated at 130°C with desirable current densities. K.T. Adjemian, S. Srinivasan, J. Benziger and A.B. Bocarsly: J. of Power Sources 109(2) 356–364 (1 July 2002).
Simulating process settings for unslaved SOFC response A common approach to reliable loadfollowing is to ‘slave’ the fuel cell response to the reactants supply subsystem (e.g. fuel processor). A change-in-power demand may be time-sensitive, however, and slaving the fuel cell response to that of the slower balanceof-plant components may not be practical. This model simulates the unrestrained loadfollowing characteristics of the Siemens Westinghouse tubular SOFC. Analysis shows that initial conditions exist which facilitate timely responses to increases in load demand, among them lower fuel utilization, higher operating voltage and optimized cell potential reduction. C. Haynes: J. of Power Sources 109(2) 365–376 (1 July 2002).
Development of 10 kWe PROX system for FCVs A preferential oxidation (PROX) reactor for a 10 kWe automotive PEM fuel cell system has been developed. The reactor is designed as a dualstage, multi-tube system. The performance is evaluated by feeding simulated gasoline reformate containing 1.2 wt% CO. The CO concentration of the treated ref ormate is <20 ppm at steady state and <30 ppm at 65% load change. Hydrogen loss in the steady state is about 1.5%, and the pressure drop across the reactor is 4 psi (0.3 bar). At startup the system takes 3 min to reduce the CO concentration to <20 ppm, although several controllable factors could shorten this. S.H. Lee, J. Han and K.-Y. Lee: J. of Power Sources 109(2) 394–402 (1 July 2002).
October 2002