Proton Exchange Membrane Water Electrolysis as a Promising Technology for Hydrogen Production and Energy Storage

Proton exchange membrane (PEM) electrolysis is industrially important as a green source of high-purity hydrogen, for chemical applications as well as energy storage. Energy capture as hydrogen via water electrolysis has been gaining tremendous interest in Europe and other parts of the world because of the higher renewable penetration on their energy grid. Hydrogen is an appealing storage medium for excess renewable energy because once stored, it can be used in a variety of applications including power generation in periods of increased demand, supplementation of the natural gas grid for increased efficiency, vehicle fueling, or use as a high-value chemical feedstock for green generation of fertilizer and other chemicals. Today, most of the cost and energy use in PEM electrolyzer manufacturing is contributed by the cell stack manufacturing processes. Current state-of-the-art electrolysis technology involves two options: liquid electrolyte and ion exchange membranes. Membrane-based systems overcome many of the disadvantages of alkaline liquid systems, because the carrier fluid is deionized water, and the membrane-based cell design enables differential pressure operation

Analysis of heat and mass transfer limitations for the combustion of methane emissions on PdO/Co3O4 coated on ceramic open cell foams

Coated ceramic open cells foams (OCFs) with catalysts offer an attractive alternative to packed bed reactors for process intensification. Here, the effect of 3 wt.% PdO on Co3O4 coated on three different OCF (alumina, silicon carbide and zirconia) was investigated toward the reaction of CH4 combustion in lean conditions. The OCFs were characterized by Raman spectroscopy and FESEM analysis. The operating regime of each OCF catalyst was investigated using a series of mass transfer resistances assuming pseudo first order reaction (large excess of oxygen). The thermal conductivity of OCF plays an important role on the overall performance of the combustion reaction in terms of heat and mass transfer. The best OCF structured catalyst was tested up to 250 hours of time-on-stream, demonstrating good stability. PdO dispersion over the structured catalyst at the fresh and aged status was assessed by STEM analysis

Application of a Coated Film Catalyst Layer Model to a High Temperature Polymer Electrolyte Membrane Fuel Cell with Low Catalyst Loading Produced by Reactive Spray Deposition Technology

In this study, a semi-empirical model is presented that correlates to previously obtained experimental overpotential data for a high temperature polymer electrolyte membrane fuel cell (HT-PEMFC). The goal is to reinforce the understanding of the performance of the cell from a modeling perspective. The HT-PEMFC membrane electrode assemblies (MEAs) were constructed utilizing an 85 wt. % phosphoric acid doped Advent TPS® membranes for the electrolyte and gas diffusion electrodes (GDEs) manufactured by Reactive Spray Deposition Technology (RSDT). MEAs with varying ratios of PTFE binder to carbon support material (I/C ratio) were manufactured and their performance at various operating temperatures was recorded. The semi-empirical model derivation was based on the coated film catalyst layer approach and was calibrated to the experimental data by a least squares method. The behavior of important physical parameters as a function of I/C ratio and operating temperature were explored

Catalyst, Membrane, Free Electrolyte Challenges, and Pathways to Resolutions in High Temperature Polymer Electrolyte Membrane Fuel Cells

High temperature polymer electrolyte membrane fuel cells (HT-PEMFCs) are being studied due to a number of benefits offered versus their low temperature counterparts, including co-generation of heat and power, high tolerance to fuel impurities, and simpler system design. Approximately 90% of the literature on HT-PEM is related to the electrolyte and, for the most part, these electrolytes all use free phosphoric acid, or similar free acid, as the ion conductor. A major issue with using phosphoric acid based electrolytes is the free acid in the electrodes. The presence of the acid on the catalyst sites leads to poor oxygen activity, low solubility/diffusion, and can block electrochemical sites through phosphate adsorption. This review will focus on these issues and the steps that have been taken to alleviate these obstacles. The intention is this review may then serve as a tool for finding a solution path in the community

Low Temperature SOFC Cathode Layer Deposited by Reactive Spray Deposition Technology (RSDT)

Present work presents the results obtained by using a direct deposition technique to make SOFC cathode materials that either significantly reduce or eliminate the need for sintering. A reference composite cathode made of 75 wt.% Sm 0.5 Sr 0.5 Co O3 (SSC) and 25 wt.% Sm 0.2 Ce 0.8 O 1.9 (SDC) has been applied on a cermet supported thin SDC electrolyte cell. Cell peak power performance was measured to be 0.49 W cm−2 operating at 600 °C after firing at 1050 °C. The measured total electrode polarization Rp(a + c) was 0.102 Ω cm2 at 600 °C. In this study a thin (~5 µm) SSC cathode has been applied by Reactive Spray Deposition Technology (RSDT) and the total polarization was reduced to 0.079 Ω cm2, indicating over 20% reduction of losses compared to the traditional cathode processing rout

Catalysts for Direct Seawater Electrolysis: Current Status and Future Prospectives

Abstract Global freshwater shortage is forcing researchers to focus on seawater electrolysis for large‐scale green hydrogen production. Seawater purification by reverse osmosis (RO) for use in conventional water electrolyzers (WEs) is another approach, however, that requires large capital investments. Alternatively, seawater can be used directly in a novel type of anion exchange membrane WE (AEMWE) which is currently under development. The AEMWEs have the advantage of using non‐precious catalysts and are less sensitive to the presence of impurities. Success in this early‐stage technology relies on the development of efficient and durable electrocatalysts. This paper provides a comprehensive review of the status and future trends for developing catalysts operating directly with seawater. Catalysts are ranked based on their activity and durability at high current densities of 500 mAcm−2 and 1000 mAcm−2. Notable anode catalysts, S−NiFe2O4, and NiFe LDH, exhibit reduced OER overpotentials of 287 mV and 296 mV at 1000 mAcm−2. Top‐performing cathode HER catalysts include HW−NiMoN‐2 h (132 mV) and Pt−Co−Mo (117 mV) at 1000 mAcm−2. Bifunctional catalysts, such as CoxPv@NC can operate below an overall voltage of 2 V at 1000 mAcm−2. This comparative analysis provides researchers and professionals with critical insights for advancing direct seawater electrolysis

Thin film Low Temperature Solid Oxide Fuel Cell (LTSOFC) by Reactive Spray Deposition Technology (RSDT)

The present work describes the effect on the performance of a SOFC when a Gd 0.2Ce 0.8O 1.9 (GDC) layer is introduced as diffusion barrier layer between the yttria stabilized zirconia (YSZ) electrolyte and the La 0.6Sr 0.4Co 1-xFe xO 3-\u3b4 (LSCF) cathode of an anode supported cell with Ni-YSZ anode. The dense, thin and fully crystalline GDC films were directly applied by RSDT, without any post-deposition heating or sintering steps. The quality of the film and performance of the cell prepared by Reactive Spray Deposition Technology (RSDT) was compared to a GDC blocking layer deposited by screen printing (SP) and then sintered at 1000\ub0C. By applying RSDT to deposit the GDC-barrier layer onto the YSZ electrolyte a lower ohmic resistance was obtained for the RSDT deposited cell vs. the SP cell. The lower resistance can be attributed to the well crystallized, thin and dense GDC layer deposited at 900\ub0C. \ua9The Electrochemical Society.Peer reviewed: YesNRC publication: Ye

Oxygen reduction reaction evaluation of platinum catalysts formed via the reactive spray deposition technique

Reactive Spray Deposition Technology (RSDT) is a fabrication process developed for the 1-step deposition of platinum catalyst, carbon support and ionomer directly onto a Nafion\uae membrane. The process involves pumping a platinumorganic solute dissolved in a combustible solvent through an atomizer. The spray is then combusted and nanosized particles of platinum are produced and subsequently cooled by a gas quench. Once the reaction plume is cooled a secondary set of nozzles is used to inject the carbon support and ionomer. The quench air cools the reactive zone enough to allow direct deposition onto a Nafion\uae electrolyte or a glassy carbon electrode. This arrangement thus realizes a process for one-step catalyst formation, dispersion onto carbon and direct deposition onto an electrolyte membrane. The independent control of the three components allows for real-time control of the carbon, platinum, and ionomer ratios in the final electrode. In this research work we examine the oxygen reduction reaction via a rotating disc three electrode set-up to understand the intrinsic activity of the as-sprayed platinum. The mass and specific activities were measured in a 0.1 M perchloric acid electrolyte under different deposition conditions and loading was verified by atomic emission spectroscopy inductively coupled plasma (AES-ICP). A range of microscopy images for visualization of the microstructure are also presented. The initial results show that the RSDT technique is capable of producing catalysts with oxygen reduction mass activity at 0.9 V of 200 mA/mgPt rotating at 1600 rpm and 30 \ub0C. \ua9 2011 by ASME.Peer reviewed: YesNRC publication: Ye

Supported and unsupported platinum catalysts prepared by a one-step dry deposition method and their oxygen reduction reactivity in acidic media

The present study examines the physical and electrochemical properties of platinum particles generated by a combustion method for use in oxygen reduction on the cathode side of a proton exchange fuel cell (PEMFC). This method employs a one-step, open-atmosphere, and dry deposition technique called reactive spray deposition technology (RSDT). The objective of this study is to characterize the intrinsic activity of the platinum produced for incorporation into low-loading cathode electrodes in high performing membrane electrode assemblies (MEA). The process allows for independent real-time control of the carbon, platinum, and ionomer ratios in the final electrode. In this research work we examine the oxygen reduction reaction via a rotating disk three electrode set-up to understand the intrinsic activity of the as-sprayed platinum as well as platinum condensed onto a carbon support. The mass and specific activities were measured in a 0.1 M perchloric acid electrolyte under different deposition conditions and loading was verified by atomic emission spectroscopy inductively coupled plasma (AES-ICP). Microscopy results indicate that the platinum particle sizes are 5 nm (\u3c3 = 2.8 nm) in diameter while TEM and XRD show that the platinum generated by the process is pure and crystalline without bulk oxides or precursor material present. The initial rotating disk electrode result shows that the RSDT technique is capable of producing catalysts with an oxygen reduction mass activity at 0.9 V of 200 mA/mgPt rotating at 1600 rpm and 30 \ub0C. The electrochemically active surface area approaches 120 m2/g for the platinum, carbon, and ionomer samples and the unsupported sample with only platinum has an active area of 92 m2/g. The rather larger surface area of the unsupported sample exists when the platinum is deposited as a highly porous nanostructured layer that allows for high penetration of reactant.Peer reviewed: YesNRC publication: Ye