Operation of PEM fuel cells at 120–150 °C to improve CO tolerance

Sulfonic acid modified perfluorocarbon polymer proton exchange membrane (PEM) fuel cells operated at elevated temperatures (120–150 °C) can greatly alleviate CO poisoning on anode catalysts. However, fuel cells with these PEMs operated at elevated temperature and atmospheric pressure typically experience low relative humidity (RH) and thus have increased membrane and electrode resistance. To operate PEM fuel cells at elevated temperature and high RH, work is needed to pressurize the anode and cathode reactant gases, thereby decreasing the efficiency of the PEM fuel cell system. A liquid-fed hydrocarbon-fuel processor can produce reformed gas at high pressure and high relative humidity without gas compression. If the anode is fed with this high-pressure, high-relative humidity stream, the water in the anode compartment will transport through the membrane and into the ambient pressure cathode structure, decreasing the cell resistance. This work studied the effect of anode pressurization on the cell resistance and performance using an ambient pressure cathode. The results show that high RH from anode pressurization at both 120 and 150 °C can decrease the membrane resistance and therefore increase the cell voltage. A cell running at 150 °C obtains a cell voltage of 0.43 V at 400 mA cm⁻² even with 1% CO in H₂. The results presented here provide a concept for the application of a coupled steam reformer and PEM fuel cell system that can operate at 150 °C with reformate and an atmospheric air cathode.     

Operation of ceria-electrolyte solid oxide fuel cells on iso-octane–air fuel mixtures

Reduced-temperature solid oxide fuel cells (SOFCs) – with thin Ce_0.85Sm_0.15O_1.925 (SDC) electrolytes, thick Ni–SDC anode supports, and composite cathodes containing La_0.6Sr_0.4Co_0.2Fe_0.8O₃ (LSCF) and SDC – were fabricated and tested with iso-octane/air fuel mixtures. An additional supported catalyst layer, placed between the fuel stream and the anode, was needed to obtain a stable output power density (e.g. 0.6 W cm⁻² at 590 °C) without anode coking. The Ru-CeO₂ catalyst produced CO₂ and H₂ at temperatures <350 °C, while H₂ and CO became predominant above 500 °C. Power densities were substantially less than for the same cells with H₂ fuel (e.g. 1.0 W cm⁻² at 600 °C), due to the dilute (≈20%) hydrogen in the fuel mixture produced by iso-octane partial oxidation. Electrochemical impedance analysis showed a main arc that represented ≈60% of the total resistance, and that increased substantially upon switching from hydrogen to iso-octane/air.     

Investigation of hydrogen production from boron compounds for pem fuel cells

This paper presents a comprehensive study of hydrogen production from sodium borohydride (NaBH₄), which is synthesized from sodium tetraborate (Na₂B₄O₇) decomposition, for proton exchange membrane (PEM) fuel cells. For this purpose, Na₂B₄O₇ decomposition reaction at 450–500 °C under hydrogen atmosphere and NaBH₄ decomposition reaction at 25–40 °C under atmospheric pressure are selected as a common temperature range in practice, and the inlet molar quantities of Na₂B₄O₇ are chosen from 1 to 6 mol with 0.5 mol interval as well. In order to form NaBH₄ solution with 7.5 wt.% NaBH₄, 1 wt.% NaOH, 91.5 wt.% H₂O, the molar quantities of NaBH₄ are determined. For a PEM fuel cell operation, the required hydrogen production rates are estimated depending on 60, 65, 70 and 75 g of catalyst used in the NaBH₄ solution at 25, 32.5 and 40 °C, respectively. It is concluded that the highest rate of hydrogen production per unit area from NaBH₄ solution at 40 °C is found to be 3.834 × 10⁻⁵ g H₂ s⁻¹ cm⁻² for 75 g catalyst. Utilizing 80% of this hydrogen production, the maximum amounts of power generation from a PEM fuel cell per unit area at 80 °C under 5 atm are estimated as 1.121 W cm⁻² for 0.016 cm by utilizing hydrogen from 75 g catalyst assisted NaBH₄ solution at 40 °C.     

Overview of the development of CO-tolerant anode electrocatalysts for proton-exchange membrane fuel cells

Poisoning of Pt anode electrocatalysts by carbon monoxide (CO) is deemed to be one of the most significant barriers to be overcome in the development of proton-exchange membrane fuel cell systems (PEMFCs). The use of CO-tolerant electrocatalysts serves as the most hopeful way to solve this problem. It is well established that Pt-based alloy systems of CO-tolerant electrocatalysts can substantially withstand the presence of CO in the fuel stream. Based on literature starting in 2000, a few efforts have still been conducted at developing a more CO-tolerant anode electrocatalyst than the traditional Pt/C or PtRu/C systems. This review introduces and discusses these efforts.Pt-based electrocatalysts, including PtSn/C, PtMo/C (atomic ratio = 5:1), PtRuMo/C (Mo = 10 wt.%), PtRu–H_xMoO₃/C and PtRu/(C nanotubes), appear to be poisoned by CO at the same, or a lower, level than traditional Pt/C or PtRu/C electrocatalysts. Platinum-free electrocatalysts, such as PdAu/C, have proven to be less strongly poisoned by CO than PtRu/C counterparts at temperatures of 60 °C.A greater tolerance to CO can be achieved by modifying the structure of the electrocatalyst. This involves the use of a composite or double-layer that is designed to make the CO react with one of the electrocatalyst in advance while the main hydrogen reacts at another layer with a traditional Pt/C electrocatalyst.     

Increasing the operation temperature of polymer electrolyte membranes for fuel cells: From nanocomposites to hybrids

Among the possible systems investigated for energy production with low environmental impact, polymeric electrolyte membrane fuel cells (PEMFCs) are very promising as electrochemical power sources for application in portable technology and electric vehicles. For practical applications, operating FCs at temperatures above 100 °C is desired, both for hydrogen and methanol fuelled cells. When hydrogen is used as fuel, an increase of the cell temperature produces enhanced CO tolerance, faster reaction kinetics, easier water management and reduced heat exchanger requirement. The use of methanol instead of hydrogen as a fuel for vehicles has several practical benefits such as easy transport and storage, but the slow oxidation kinetics of methanol needs operating direct methanol fuel cells (DMFCs) at intermediate temperatures. For this reason, new membranes are required. Our strategy to achieve the goal of operating at temperatures above 120 °C is to develop organic/inorganic hybrid membranes. The first approach was the use of nanocomposite class I hybrids where nanocrystalline ceramic oxides were added to Nafion. Nanocomposite membranes showed enhanced characteristics, hence allowing their operation up to 130 °C when the cell was fuelled with hydrogen and up to 145 °C in DMFCs, reaching power densities of 350 mW cm⁻². The second approach was to prepare Class II hybrids via the formation of covalent bonds between totally aromatic polymers and inorganic clusters. The properties of such covalent hybrids can be modulated by modifying the ratio between organic and inorganic groups and the nature of the chemical components allowing to reach high and stable conductivity values up to 6.4 × 10⁻² S cm⁻¹ at 120 °C.     

Solid oxide fuel cells operated by internal partial oxidation reforming of iso-octane

Two types of solid oxide fuel cells (SOFCs), with thin Ce_0.85Sm_0.15O_1.925 (SDC) or 8 mol% Y₂O₃-stabilized ZrO₂ (YSZ) electrolytes, were fabricated and tested with iso-octane/air fuel mixtures. An additional Ru–CeO₂ catalyst layer, placed between the fuel stream and the anode, was needed to obtain a stable output power density without anode coking. Thermodynamic analysis and catalysis experiments showed that H₂ and CO were primary reaction products at ≈750 °C, but that these decreased and H₂O and CO₂ increased as the operating temperature dropped below ≈600 °C. Power densities for YSZ cells were 0.7 W cm⁻² at 0.7 V and 790 °C, and for SDC cells were 0.6 W cm⁻² at 0.6 V and 590 °C. Limiting current behavior was observed due to the relatively low (≈20%) H₂ content in the reformed fuel.     

Dynamic behaviour of SOFC short stacks

Electrical output behaviour obtained on solid oxide fuel cell stacks, based on planar anode supported cells (50 or 100 cm² active area) and metallic interconnects, is reported. Stacks (1–12 cells) have been operated with cathode air and anode hydrogen flows between 750 and 800 °C operating temperature. At first polarisation, an activation phase (increase in power density) is typically observed, ascribed to the cathode but not clarified. Activation may extend over days or weeks. The materials are fairly resistant to thermal cycling. A 1-cell stack cycled five times in 4 days at heating/cooling rates of 100–300 K h⁻¹, showed no accelerated degradation. In a 5-cell stack, open circuit voltage (OCV) of all cells remained constant after three full cycles (800–25 °C). Power output is little affected by air flow but markedly influenced by small fuel flow variation. Fuel utilisation reached 88% in one 5-cell stack test. Performance homogeneity between cells lay at ±4–8% for three different 5- or 6-cell stacks, but was poor for a 12-cell stack with respect to the border cells. Degradation of a 1-cell stack operated for 5500 h showed clear dependence on operating conditions (cell voltage, fuel conversion), believed to be related to anode reoxidation (Ni). A 6-cell stack (50 cm² cells) delivering 100 W_el at 790 °C (1 kW_el L⁻¹ or 0.34 W cm⁻²) went through a fuel supply interruption and a thermal cycle, with one out of the six cells slightly underperforming after these events. This cell was eventually responsible (hot spot) for stack failure.     

Thermodynamic equilibrium calculations of hydrogen production from the combined processes of dimethyl ether steam reforming and partial oxidation

Thermodynamic analyses of producing a hydrogen-rich fuel-cell feed from the combined processes of dimethyl ether (DME) partial oxidation and steam reforming were investigated as a function of oxygen-to-carbon ratio (0.00–2.80), steam-to-carbon ratio (0.00–4.00), temperature (100 °C–600 °C), pressure (1–5 atm) and product species.Thermodynamically, dimethyl ether processed with air and steam generates hydrogen-rich fuel-cell feeds; however, the hydrogen concentration is less than that for pure DME steam reforming. Results of the thermodynamic processing of dimethyl ether indicate the complete conversion of dimethyl ether to hydrogen, carbon monoxide and carbon dioxide for temperatures greater than 200 °C, oxygen-to-carbon ratios greater than 0.00 and steam-to-carbon ratios greater than 1.25 at atmospheric pressure (P = 1 atm). Increasing the operating pressure has negligible effects on the hydrogen content. Thermodynamically, dimethyl ether can produce concentrations of hydrogen and carbon monoxide of 52% and 2.2%, respectively, at a temperature of 300 °C, and oxygen-to-carbon ratio of 0.40, a pressure of 1 atm and a steam-to-carbon ratio of 1.50. The order of thermodynamically stable products (excluding H₂, CO, CO₂, DME, NH₃ and H₂O) in decreasing mole fraction is methane, ethane, isopropyl alcohol, acetone, n-propanol, ethylene, ethanol and methyl-ethyl ether; trace amounts of formaldehyde, formic acid and methanol are observed.Ammonia and hydrogen cyanide are also thermodynamically favored products. Ammonia is favored at low temperatures in the range of oxygen-to-carbon ratios of 0.40–2.50 regardless of the steam-to-carbon ratio employed. The maximum ammonia content (i.e., 40%) occurs at an oxygen-to-carbon ratio of 0.40, a steam-to-carbon ratio of 1.00 and a temperature of 100 °C. Hydrogen cyanide is favored at high temperatures and low oxygen-to-carbon ratios with a maximum of 3.18% occurring at an oxygen-to-carbon ratio of 0.40 and a steam-to-carbon ratio of 0.00 in the temperature range of 400 °C–500 °C. Increasing the system pressure shifts the equilibrium toward ammonia and hydrogen cyanide.     

Screen-printed thin YSZ films used as electrolytes for solid oxide fuel cells

A thin yttria-stabilized zirconia (8 mol% YSZ) film was successfully fabricated on a NiO-YSZ anode substrate by a screen-printing technique. The scanning electron microscope (SEM) results suggested that the YSZ film thickness was about 31 μm after sintering at 1400 °C for 4 h in air. A 60 wt% La_0.7Sr_0.3MnO₃ + 40 wt% YSZ was screen-printed onto the YSZ film surface as cathode. A single cell was tested from 650 to 850 °C using hydrogen as fuel and ambient air as oxidant, which showed an open circuit voltage (OCV) of 1.02 V and a maximum power density of 1.30 W cm⁻² at 850 °C. The OCV was higher than 1.0 V, which suggested that the YSZ film was quite dense and that the fuel gas leakage through the YSZ film was negligible. Screen-printing can be a promising method for manufacturing YSZ films for solid oxide fuel cells (SOFCs).     

A study of Ni + 8YSZ/8YSZ/La0.6Sr0.4CoO3−δ ITSOFC fabricated by atmospheric plasma spraying

An intermediate temperature solid oxide fuel cell (ITSOFC) based on 8YSZ electrolyte, La_0.6Sr_0.4CoO_3−δ (LSCo) cathode, and Ni − 8YSZ anode coatings were consecutively deposited onto a porous Ni-plate substrate by atmospheric plasma spraying (APS). The spray parameters including current, argon and hydrogen flow rate, and powder feed rate were investigated by an orthogonal experiment to fabricate a thin gas-tight 8YSZ electrolyte coating (80 μm). By proper selection of the spray parameters to decrease the particles velocity and temperature, the sprayed NiO + 8YSZ coating after reducing with hydrogen shows a good electrocatalytic activity for H₂ oxidation. With the same treatment, 100–170 μm dimensions LSCo particle could keep phase structure after spraying. And the deposited LSCo cathode shows a good cathode performance and chemical compatibility with 8YSZ electrolyte after operating at 800 °C for 50 h. Output power density of the sprayed cell achieved 410 mW cm⁻² at 850 °C and 260 mW cm⁻² at 800 °C. Electrochemical characterization indicated that IR drop of 8YSZ electrolyte, cathodic polarization, and the contact resistance at LSCo/8YSZ interface were the main factors restricting the cell performance. The results suggested that the use of APS cell allowed the reduction of the operating temperature of the SOFC to below 850 °C with lower production costs.     

Proton-conducting methacrylate–silica sol–gel membranes containing tungstophosphoric acid

The increase of the operation temperature in proton-exchange membrane fuel cell (PEMFC) above 100 °C is a great concern for the application of this type of cells in electric vehicles. Hybrid organic–inorganic membranes with nano-sized interfaces can combine the main properties to meet this objective. Methacrylate–silica covalent hybrid membranes have been synthesised by polymerization of 2-hydroxyethyl methacrylate and 3-methacryloxypropyl trimethoxysilane, and hydrolysis–polycondensation of alkoxide radicals. Tungstophosphoric acid hydrate was incorporated to endow the membranes with proton conductivity. The composition and synthesis conditions to promote organic polymerisation and sol–gel condensation avoiding phase separation have been optimised. The structural analysis shows homogeneous membranes without phase separation. The water retention properties provided by SiO₂ and tungstophosphoric acid leads to high proton conductivity (maximum values around 3 × 10⁻² S cm⁻¹) at 100–150 °C. A 0.5 M % of Tungstophosphoric acid (PWA) is enough to build well-connected paths for proton conduction.     

Thermodynamic evaluation of methanol steam reforming for hydrogen production

Thermodynamic equilibrium of methanol steam reforming (MeOH SR) was studied by Gibbs free minimization for hydrogen production as a function of steam-to-carbon ratio (S/C = 0–10), reforming temperature (25–1000 °C), pressure (0.5–3 atm), and product species. The chemical species considered were methanol, water, hydrogen, carbon dioxide, carbon monoxide, carbon (graphite), methane, ethane, propane, i-butane, n-butane, ethanol, propanol, i-butanol, n-butanol, and dimethyl ether (DME). Coke-formed and coke-free regions were also determined as a function of S/C ratio.Based upon a compound basis set MeOH, CO₂, CO, H₂ and H₂O, complete conversion of MeOH was attained at S/C = 1 when the temperature was higher than 200 °C at atmospheric pressure. The concentration and yield of hydrogen could be achieved at almost 75% on a dry basis and 100%, respectively. From the reforming efficiency, the operating condition was optimized for the temperature range of 100–225 °C, S/C range of 1.5–3, and pressure at 1 atm. The calculation indicated that the reforming condition required from sufficient CO concentration (<10 ppm) for polymer electrolyte fuel cell application is too severe for the existing catalysts (T_r = 50 °C and S/C = 4–5). Only methane and coke thermodynamically coexist with H₂O, H₂, CO, and CO₂, while C₂H₆, C₃H₈, i-C₄H₁₀, n-C₄H₁₀, CH₃OH, C₂H₅OH, C₃H₇OH, i-C₄H₉OH, n-C₄H₉OH, and C₂H₆O were suppressed at essentially zero. The temperatures for coke-free region decreased with increase in S/C ratios. The impact of pressure was negligible upon the complete conversion of MeOH.     

Sulfonated poly(ether sulfone) for universal polymer electrolyte fuel cell operations

The performances of the proton exchange membrane fuel cell (PEMFC), direct formic acid fuel cell (DFAFC) and direct methanol fuel cell (DMFC) with sulfonated poly(ether sulfone) membrane are reported. Pt/C was coated on the membrane directly to fabricate a MEA for PEMFC operation. A single cell test was carried out using H₂/air as the fuel and oxidant. A current density of 730 mA cm⁻² at 0.60 V was obtained at 70 °C. Pt–Ru (anode) and Pt (cathode) were coated on the membrane for DMFC operations. It produced 83 mW cm⁻² maximum power density. The sulfonated poly(ether sulfone) membrane was also used for DFAFC operation under several different conditions. It showed good cell performances for several different kinds of polymer electrolyte fuel cell applications.     

Hydrogen production for fuel cells through methane reforming at low temperatures

Hydrogen production for fuel cells through methane (CH₄) reforming at low temperatures has been investigated both thermodynamically and experimentally. From the thermodynamic equilibrium analysis, it is concluded that steam reforming of CH₄ (SRM) at low pressure and a high steam-to-CH₄ ratio can be achieved without significant loss of hydrogen yield at a low temperature such as 550 °C. A scheme for the production of hydrogen for fuel cells at low temperatures by burning the unconverted CH₄ to supply the heat for SRM is proposed and the calculated value of the heat-balanced temperature is 548 °C. SRM with and/or without the presence of oxygen at low temperatures is experimentally investigated over a Ni/Ce–ZrO₂/θ-Al₂O₃ catalyst. The catalyst shows high activity and stability towards SRM at temperatures from 400 to 650 °C. The effects of O₂:CH₄ and H₂O:CH₄ ratios on the conversion of CH₄, the hydrogen yield, the selectivity for carbon monoxide, and the H₂:CO ratio are investigated at 650 °C with a constant CH₄ space velocity. Results indicate that CH₄ conversion increases significantly with increasing O₂:CH₄ or H₂O:CH₄ ratio, and the hydrogen content in dry tail gas increases with the H₂O:CH₄ ratio.     

Effect of injection timing on the exhaust emissions of a diesel engine using diesel–methanol blends

Environmental concerns and limited resource of petroleum fuels have caused interests in the development of alternative fuels for internal combustion (IC) engines. For diesel engines, alcohols are receiving increasing attention because they are oxygenated and renewable fuels. Therefore, in this study, the effect of injection timing on the exhaust emissions of a single cylinder, naturally aspirated, four-stroke, direct injection diesel engine has been experimentally investigated by using methanol-blended diesel fuel from 0% to 15% with an increment of 5%. The tests were conducted for three different injection timings (15°, 20° and 25 °CA BTDC) at four different engine loads (5 Nm, 10 Nm, 15 Nm, 20 Nm) at 2200 rpm. The experimental test results showed that Bsfc, NO_x and CO₂ emissions increased as BTE, smoke opacity, CO and UHC emissions decreased with increasing amount of methanol in the fuel mixture. When compared the results to those of original injection timing, NO_x and CO₂ emissions decreased, smoke opacity, UHC and CO emissions increased for the retarded injection timing (15 °CA BTDC). On the other hand, with the advanced injection timing (25 °CA BTDC), decreasing smoke opacity, UHC and CO emissions diminished, and NO_x and CO₂ emissions boosted at all test conditions. In terms of Bsfc and BTE, retarded and advanced injection timings gave negative results for all fuel blends in all engine loads.     

Ammonia fuel cell using doped barium cerate proton conducting solid electrolytes

Proton-conducting solid electrolytes composed of gadolinium-doped barium cerate (BCG) or gadolinium and praseodymium-doped barium cerate (BCGP) were tested in an intermediate-temperature fuel cell in which hydrogen or ammonia was directly fed. At 700 °C, BCG electrolytes with porous platinum electrodes showed essentially no loss in performance in pure hydrogen. Under direct ammonia at 700 °C, power densities were only slightly lower compared to pure hydrogen feed, yielding an optimal value of 25 mW cm⁻² at a current density of 50 mA cm⁻². This marginal difference can be attributed to a lower partial pressure of hydrogen caused by the production of nitrogen when ammonia is decomposed at the anode.A comparative test using BCGP electrolyte showed that the doubly doped barium cerate electrolyte performed better than BCG electrolyte. Overall fuel cell performance characteristics were enhanced by approximately 40% under either hydrogen or ammonia fuels using BCGP electrolyte. At 700 °C using direct ammonia feed, power density reached 35 mW cm⁻² at a current density of approximately 75 mA cm⁻². Minimal loss of performance was noted over approximately 100 h on-stream in alternating hydrogen/ammonia fuels.     

A 28-W portable direct borohydride–hydrogen peroxide fuel-cell stack

A 28-W direct borohydride–hydrogen peroxide fuel-cell stack operating at 25 °C is reported for contemporary portable applications. The fuel cell operates with the peak power-density of ca. 50 mW cm⁻² at 1 V. This performance is superior to the anticipated power-density of 9 mW cm⁻² for a methanol–hydrogen peroxide fuel cell. Taking the fuel efficiency of the sodium borohydride–hydrogen peroxide fuel cell as 24.5%, its specific energy is ca. 2 kWh kg⁻¹. High power-densities can be achieved in the sodium borohydride system because of its ability to provide a high concentration of reactants to the fuel cell.     

Dependence of high-temperature PEM fuel cell performance on Nafion® content

Operating a proton exchange membrane (PEM) fuel cell at elevated temperatures (above 100 °C) has significant advantages, such as reduced CO poisoning, increased reaction rates, faster heat rejection, easier and more efficient water management and more useful waste heat. Catalyst materials and membrane electrode assembly (MEA) structure must be considered to improve PEM fuel cell performance. As one of the most important electrode design parameters, Nafion^® content was optimized in the high-temperature electrodes in order to achieve high performance. The effect of Nafion^® content on the electrode performance in H₂/air or H₂/O₂ operation was studied under three different operation conditions (cell temperature (°C)/anode (%RH)/cathode (%RH)): 80/100/75, 100/70/70 and 120/35/35, all at atmospheric pressure. Different Nafion^® contents in the cathode catalyst layers, 15–40 wt%, were evaluated. For electrodes with 0.5 mg cm⁻² Pt loading, cell voltages of 0.70, 0.68 and 0.60 V at a current density of 400 mA cm⁻² were obtained at 35 wt% Nafion^® ionomer loading, when the cells were operated at the three test conditions, respectively. Cyclic voltammetry was conducted to evaluate the electrochemical surface area. The experimental polarization curves were analyzed by Tafel slope, catalyst activity and diffusion capability to determine the influence of the Nafion^® loading, mainly associated with the cathode.     

Progress in the development of a high-power,direct ethylene glycol fuel cell (DEGFC)

We recently reported on a high-power nanoporous proton-conducting membrane (NP-PCM)-based direct methanol fuel cell (DMFC) operated with triflic acid. However, accompanying the advantages of methanol as a fuel, such as low cost and ease of handling and storage, are several pronounced disadvantages: toxicity, high flammability, low boiling point (65 °C) and the strong tendency to pass through the polymer-exchange membrane (high crossover). The focus of this work is the development of a high-power direct ethylene glycol fuel cell (DEGFC) based on the NP-PCM. Ethylene glycol (EG) has a theoretical capacity 17% higher than that of methanol in terms of Ah ml⁻¹ (4.8 and 4, respectively); this is especially important for portable electronic devices. It is also a safer (bp 198 °C) fuel for direct-oxidation fuel cell (DOFC) applications. Maximum power densities of 320 mW cm⁻² (at 0.32 V) at 130 °C have been achieved in the DEGFC fed with 0.72 M ethylene glycol in 1.7 M triflic acid at 3 atm at the anode and with dry air at 3.7 atm at the cathode. The cell platinum loading was 4 mg Pt cm⁻² on each electrode. The overpotentials at the cathodes and at the anodes of the DEGFC and DMFC were measured, compared and discussed.     

A 75-kW methanol reforming fuel cell system

A 75-kW methanol reforming fuel cell system, which consists of a fuel cell system and a methanol auto-thermal reforming fuel processor has been developed at Dalian Institute of Chemical Physics, Chinese Academy of Sciences (CAS). The core of the fuel cell system is a group of CO tolerant PEMFC stacks with a double layer composite structured anode. The fuel cell stacks show good CO tolerance even though 140 ppm CO was present in the reformate stream during transients. The auto-thermal reforming (ATR) fuel cell processor could adiabatically produce a suitable reformate without external energy consumption. The output of hydrogen-rich reformate was approximately 120 N m³ h⁻¹ with a H₂ content near 53% and the CO concentrations generally were under 30 ppm. The fuel cell system was integrated with the methanol reforming fuel processor and the peak power output of the fuel cell system exceeded 75 kW in testing. The hydrogen utilization approached 70% in the fuel cell system.