Preparation and Optimization of Porous Membrane Electrodes via Gradient Coating in Hydrogen Fuel Cell

Fuel cells are considered to be one of the ideal alternatives to traditional fossil energy conversion devices.Membrane electrodes are the core components in the hydrogen fuel cells.Our work reported the synthesis of the Pt/C catalysts with different Pt loading,and by changing the Nafion content,hot pressing temperature and hot pressing pressure,the catalyst coated membrane(CCM)spraying process was optimized.Moreover,the three-dimensional structure model of the single battery membrane electrode was studied quantitatively,and the porous membrane electrode with gradient distribution was fabricated under optimized processing conditions,with excellent electrical performance.

Design and Key Technology of Oil-Free Centrifugal Air Compressor for Hydrogen Fuel Cell

For a 120 kW hydrogen fuel cell system,a centrifugal air compressor with fixed power of 22 kW fuel cell is designed.Firstly,the theoretical calculation is carried out for the aerodynamic characteristics of a ultra-high-speed permanent magnet synchronous motor,an air compressor,and an aerodynamic foil bearing.Then,a prototype is trial-produced and a related test bench is built for test verification.Finally,both the simulation and test results indicate that the designed centrifugal air compressor meets the overall requirements of the hydrogen fuel cell system,and the relevant conclusions provide both theoretical and experimental references for the subsequent series development and design of the centrifugal air compressor.

Performance assessment of a spiral methanol to hydrogen fuel processor for fuel cell applications

A novel design of plate-type microchannel reactor has been developed for fuel cell-grade hydrogen production.Commercial Cu/Zn/Al2O3 was used as catalyst for the reforming reaction,and its effectiveness was evaluated on the mole fraction of products,methanol conversion,hydrogen yield and the amount of carbon monoxide under various operating conditions.Subsequently,0.5 wt% Ru/Al2O3 as methanation catalyst was prepared by impregnation method and coupled with MSR step to evaluate the capability of methanol processor for CO reduction.Based on the experimental results,the optimum conditions were obtained as feed flow rate of 5mL/h and temperature of 250℃,leading to a low CO selectivity and high H2 yield.The designed reformer with catalyst coated layer was compared with the conventional packed bed reformer at the same operating conditions.The constructed fuel processor had a good performance and excellent capability for on-board hydrogen production.

Numerical Study on the Hydrogen Fueled SI Engine Combustion Optimization through a Combined Operation of DI and PFI Strategies

As the practicability of a hydrogen-fueled economy emerges, intermediate technologies would be necessary for the transition between hydrocarbon fueled internal combustion engines and hydrogen powered fuel cells. In the present study, the hydrogen engine efficiency and the load control are the two main parameters that will be improved by using the combined operation of in-cylinder direct fuel injection (DI) and port fuel injection (PFI) strategies to obtain maximum engine power outputs with acceptable efficiency equivalent to gasoline engines. Wide open throttle (WOT) operation has been used to take advantage of the associated increase in engine efficiency, in which the loads have been regulated with mixture richness (qualitative control) instead of volumetric efficiency (quantitative control). The capabilities of a 3D-CFD code have been developed and employed to simulate the whole engine physicochemical process which includes the hydrogen injection through the intake manifold (PFI) and/or the hydrogen DI in the engine compression stroke. Conditions with simulated PFI, PFI + DI and DI have been analyzed to study the effects of mixture preparation behaviors on the hydrogen ignition and its flame propagation inside the engine combustion chamber. Numerically, the CFD code has been intensively validated against experimental engine data which provided remarkable agreement in terms of in-cylinder pressure history evaluation.

Hydrogen Smart-Grids: Smart Metering of Electricity from Hydrogen Fuel Cells

In the last decade, increasing applications of information technology (IT) within power industry has become a significant reality. As distributed power networks are gaining importance and renewables are getting a bigger ratio within energy production, Smart Grid applications have become essential, especially due to the intermittent nature of renewable energy resources. Smart Grid is a sustainable energy system that measures, checks, and controls the generation, transmission, and consumption of electrical energy in grids on all voltage levels. Smart Grid experts are driving forward the development of effective communication and information technologies for the build-up of intelligent power supply networks. Examples of these are control systems for the realization of virtual power plants, intelligent consumer data acquisition systems, and smart distribution management systems. Fuel cell-based hydrogen electricity, in comparison to other renewable energy sources, is more stable and predictable. Yet hydrogen power and smart-grids have many application points, mainly as means of energy storage. This study claims that hydrogen energy and smart-grids could also engage through an appliance of IT managed metering of hydrogen power production. Smart metering and management of hydrogen fuel cells would enable advanced planning of short-to-mid-term power productions and thus foster use of hydrogen power within distributed networks, as local community or industrial applications.

PtCu subnanoclusters epitaxial on octahedral PtCu/Pt skin matrix as ultrahigh stable cathode electrocatalysts for room-temperature hydrogen fuel cells

Achieving stable surface structures of metal catalysts is an extreme challenge for obtaining long-term durability and meeting industrial application requirements.We report a new class of metal catalyst,Pt-rich PtCu heteroatom subnanoclusters epitaxially grown on an octahedral PtCu alloy/Pt skin matrix(PtCu1.60),for the oxygen reduction reaction(ORR)in an acid electrolyte.The PtCu1.60/C exhibits an 8.9-fold enhanced mass activity(1.42 A·mgPt^(−1))over that of commercial Pt/C(0.16 A·mgPt^(−1)).The PtCu1.60/C exhibits 140,000 cycles durability without activity decline and surface PtCu cluster stability owing to unique structure derived from the matrix and epitaxial growth pattern,which effectively prevents the agglomeration of clusters and loss of near-surface active sites.Structure characterization and theoretical calculations confirm that Pt-rich PtCu clusters favor ORR activity and thermodynamic stability.In room-temperature polymer electrolyte membrane fuel cells,the PtCu1.60/C shows enhanced performance and delivers a power density of 154.1/318.8 mW·cm^(−2)and 100 h/50 h durability without current density decay in an air/O_(2)feedstock.

Analysis of the Influence of Geometrical Parameters on the Performance of a Proton Exchange Membrane Fuel Cell

A suitable channel structure can lead to efficient gas distribution and significantly improve the power density of fuel cells.In this study,the influence of two channel design parameters is investigated,namely,the ratio of the channel width to the bipolar plate ridge width(i.e.,the channel ridge ratio)and the channel depth.The impact of these parameters is evaluated with respect to the flow pattern,the gas composition distribution,the temperature field and the fuel cell output capability.The results show that a decrease in the channel ridge ratio and an increase in the channel depth can effectively make the distributions of velocity,temperature and concentration more uniform in each channel and improve the output capability of the fuel cell.An increase in the channel ridge ratio and depth obviously reduces the flow resistance and improves the flow characteristics.

Energy Security Planning for Hydrogen Fuel Cell Vehicles in Large-Scale Events:A Case Study of Beijing 2022 Winter Olympics

Energy security planning is fundamental to safeguarding the traffic operation in large-scale events.To guarantee the promo-tion of green,zero-carbon,and environmental-friendly hydrogen fuel cell vehicles(HFCVs)in large-scale events,a five-stage planning method is proposed considering the demand and supply potential of hydrogen energy.Specifically,to meet the requirements of the large-scale events’demand,a new calculation approach is proposed to calculate the hydrogen amount and the distribution of hydrogen stations.In addition,energy supply is guaranteed from four aspects,namely hydrogen produc-tion,hydrogen storage,hydrogen delivery,and hydrogen refueling.The emergency plan is established based on the overall support plan,which can realize multi-dimensional energy security.Furthermore,the planning method is demonstrative as it powers the Beijing 2022 Winter Olympics as the first“green”Olympic,providing both theoretical and practical evidence for the energy security planning of large-scale events.This study provides suggestions about ensuring the energy demand after the race,broadening the application scenarios,and accelerating the application of HFCVs.

Passive electrochemical hydrogen recombiner for hydrogen safety systems:prospects

This paper presents the concept of a passive electrochemical hydrogen recombiner(PEHR).The reaction energy of the recombination of hydrogen and oxygen is used as a source of electrical energy according to the operating principle for hydrogen fuel cells to establish forced circulation of the hydrogen mixture as an alternative to natural circulation(as is not utilized in conventional passive autocatalytic hydrogen recombiners currently used in nuclear power plants(NPPs)).The proposed concept of applying the physical operation principles of a PEHR based on a fuel cell simultaneously increases both productivity in terms of recombined hydrogen and the concentration threshold of flameless operation(the‘ignition’limit).Thus,it is possible to reliably ensure the hydrogen explosion safety of NPPs under all conditions,including beyond-design accidents.An experimental setup was assembled to test a laboratory sample of a membrane electrode assembly(MEA)at various hydrogen concentrations near the catalytic surfaces of the electrodes,and the corresponding current–voltage characteristics were recorded.The simplest MEA based on the Advent P1100W PBI membrane demonstrated stable performance(delivery of electrical power)over a wide range of hydrogen concentrations.

Abating transport GHG emissions by hydrogen fuel cell vehicles： Chances for the developing world

Fuel cell vehicles, as the most promising clean vehicle technology for the future, represent the major chances for the developing world to avoid high-carbon lock-in in the transportation sector. In this paper, by taking China as an example, the unique advantages for China to deploy fuel cell vehicles are reviewed. Subsequently, this paper analyzes the greenhouse gas （GHG） emissions from 19 fuel cell vehicle utilization pathways by using the life cycle assessment approach. The results show that with the current grid mix in China, hydrogen from water electro- lysis has the highest GHG emissions, at 3.10 kgCO2/km, while by-product hydrogen from the chlor-alkali industry has the lowest level, at 0.08 kgCO2/krn. Regarding hydrogen storage and transportation, a combination of gas-hydrogen road transportation and single compression in the refueling station has the lowest GHG emissions. Regarding vehicle operation, GHG emissions from indirect methanol fuel cell are proved to be lower than those from direct hydrogen fuel cells. It is recommended that although fuel cell vehicles are promising for the developing world in reducing GHG emissions, the vehicle technology and hydrogen production issues should be well addressed to ensure the life-cycle low-carbon performance.

The Use of Hydrogen as a Fuel for Inland Waterway Units

关于常规石块的普遍使用的有害效果增强担心一般来说在海洋的领域里并且在内燃机造成，导致了努力并且向研究指导大大写的投资的广阔数量，持续其他的精力的开发采购原料。最答应之一并且这些来源丰富是氢。第一，当前的石块燃料的使用被讨论集中于排出物和经济方面作为一种合适的可能的选择与氢的特别参考为新、更干净、可更新的燃料强调需要。氢性质，生产和存储方法然后从节俭的观点与它的适用性一起被考察。最后，为在内燃机的氢的使用的费用分析被执行为柴油机作为代替说明它的使用的好处。这的结果花费了 98% 大写的开销被设备消费的分析表演，并且设备的 68.3% 全部的费用在太阳的光电的房间上被花。因为它是大约 10 亿的高起始的费用，氢植物作为一个大投资工程被分类 US$ ；但是因为氢以一个完全绿的方法被生产，这被认为正当。当氢被用作燃料时，没有有害排出物被获得。

A new cathode using CeO_2/MWNT for hydrogen peroxide synthesis through a fuel cell

Catalyst using CeO2/MWNT（multi-walled carbon nanotube） was prepared by chemical deposition method and was applied to prepare the cathode of fuel cell for hydrogen peroxide synthesis.Effect of catalyst loading, flow rate of aqueous solution, and KOH concentration on hydrogen peroxide synthesis were investigated.Experimental results indicated that hydrogen peroxide concentration approached 275 mmol/L given 25% of CeO2/MWNT, 18 ml/h of aqueous solution, and 5 mol/L of KOH concentration.Moreover, the reaction mechanism was further discussed.The results indicated that MWNT and cerium oxide were the synergism to produce hydrogen peroxide.Increase of KOH concentration not only reduced the apparent cell resistance but also increased the open-circuit voltage.

Synergistic effect of polyoxometalate solution and TiO_2 under UV irradiation to catalyze formic acid degradation and their application in the fuel cell and hydrogen evolution

The synergistic effect of H_3PMo_(12)O_(40) or H_3PW_(12)O_(40) polyoxometalate solution(POM) and TiO_2 to catalyze formic acid oxidation was investigated. Under UV irradiation, hole and electron were photogenerated by TiO_2. Formic acid was oxided by the photogenerated hole and photogenerated electron was transferred to reduce polyoxometalate. With this design, formic acid can be converted into electricity in the fuel cell and hydrogen can be generated in the electrolysis cell without noble metal catalyst. Unlike other noble metal catalysts applied in the fuel cells and electrolysis cell, POM and TiO_2 are stable and low cost. The maximum output power density of liquid formic acid fuel cell after 12 h UV irradiation is 5.21 mW/cm^2 for phosphmolybdic acid and 22.81 m W/cm^2 for phosphotungstic acid respectively. The applied potential for the hydrogen evolution is as low as 0.8 V for phosphmolybdic acid and 0.6 V for phosphotungstic acid.

Study on Production of Hydrogen from Methane for Proton Exchange Membrane Fuel Cell

The hydrogen production from methane for proton exchange membrane fuel cell (PEMFC) was studied experimentally. The conversion rate of methane under different steam carbon ratios, the effect of the different excess air ratios on the constituents of the gas produced, the permeability of hydrogen under different pressure differences, and the effect of different system pressure on the reaction enthalpy of hydrogen were obtained. The results lay the basis for the production of hydrogen applicable to PEMFC, moreover, provide a new way for the comprehensive utilization of the coal bed methane.

Amine axial ligand-coordinated cobalt phthalocyanine-based catalyst for flow-type membraneless hydrogen peroxide fuel cell or enzymatic biofuel cell

In this study,an amine-coordinated cobalt phthalocyanine(CoPc)-based anodic catalyst was fabricated by a facile process,to enhance the performance of hydrogen peroxide fuel cells(HPFCs) and enzymatic biofuel cells(EBCs).For this purpose,polyethyleneimine(PEI) was added onto the reduced graphene oxide and CoPc composite(RGO/CoPc) to create abundant NH2 axial ligand groups,for anchoring the Co core within the CoPc.Owing to the PEI addition,the onset potential of the hydrogen peroxide oxidation reaction was shifted by 0.13 V in the negative direction(0.02 V) and the current density was improved by 1.92 times(1.297 mA cm^(-2)),compared to those for RGO/CoPc(0.15 V and 0.676 mA cm^(-2),respectively),due to the formation of donor-acceptor dyads and the prevention of CoPc from leaching out.The biocatalyst using glucose oxidase(GOx)([RGO/CoPc]/PEI/GOx) showed a better onset potential and catalytic activity(0.15 V and 318.7 μA cm^(-2)) than comparable structures,as well as significantly improved operational durability and long-term stability.This is also attributed to PEI,which created a favorable microenvironment for the enzyme.The maximum power densities(MPDs) and open-circuit voltages(OCVs) obtained for HPFCs and EBCs using the suggested catalyst were 105.2±1.3 μW cm^(-2)(0.317±0.003 V) and 25.4±0.9 μW cm^(-2)(0.283±0.007 V),respectively.This shows that the amine axial ligand effectively improves the performance of the actual driving HPFCs and EBCs.

Comparative study on pressure swing adsorption system for industrial hydrogen and fuel cell hydrogen

In order to improve the design of PSA system for fuel cell hydrogen production,a non-isothermal model of eight-bed PSA hydrogen process with five-component(H_(2)/N_(2)/CH_(4)/CO/CO_(2)=74.59%/0.01%/4.2%/2.5%/18.7%(vol))four-stage pressure equalization was developed in this article.The model adopts a composite adsorption bed of activated carbon and zeolite 5 A.In this article,pressure variation,temperature field and separation performance are stimulated,and also effect of providing purge(PP)differential pressure and the ratio of activated carbon to zeolite 5 A on separation performance in the process of producing industrial hydrogen(CO content in hydrogen is 10μl·L^(-1))and fuel cell hydrogen(CO content is 0.2μl·L^(-1))are compared.The results show that Run 3,when the CO content in hydrogen is 10μl·L^(-1),the hydrogen recovery is 89.8%,and the average flow rate of feed gas is 0.529 mol·s^(-1);When the CO content in hydrogen is 0.2μl·L^(-1),the hydrogen recovery is 85.2%,and the average flow rate of feed gas is 0.43 mol·s^(-1).With the increase of PP differential pressure,hydrogen recovery first increases and then decreases,reaching the maximum when PP differential pressure is 0.263 MPa;With the decrease of the ratio of activated carbon to zeolite 5 A,the hydrogen recovery increases gradually.When the CO content in hydrogen is 0.2μl·L^(-1) the hydrogen recovery increases more obviously,from 83.96%to 86.37%,until the ratio of activated carbon to zeolite 5 A decreases to 1.At the end of PP step,no large amount of CO_(2) in gas or solid phase enters the zeolite 5 A adsorption bed,while when the CO content in hydrogen is 10μl·L^(-1),and the ratio of carbon to zeolite 5 A is less than 1.4,more CO_(2) will enter the zeolite 5 A bed.

Paper-like Microfibrous Nickel Catalyst for Hydrogen Production via NH_3 Decomposition in Fuel Cell Applications

A sinter-locked three-dimensional network of microfibrous nickel catalyst has been fabricated based on wet layup papermaking and sintering processes and this novel approach permits the production of -11 W fuel cell power H2 via NH3 decomposition with a conversion of 97% at 750 ℃ in a bed of 0.6 cm^3.