Influence of Ammonia Contamination on HT-PEM Fuel Cell Platinum Catalyst

Abstract

DLR Institute of Networked Energy Systems  Development of technologies and concepts for energy supply based on renewables  Department Fuel Cells • DLR Institute of Engineering Thermodynamics  Research into the field of efficient energy storage systems  Department Electrochemical Energy Technology in progress The group Characterisation merges into the group HT-PEM. -Investigation of aging processes in (LT-and HT-PEM) fuel cells and development of cell components. -Bipolar plates, membranes, catalysts, electrodes, membrane electrode assemblies, single cells and short stacks.

Efficient NH3-Tolerant Nickel-Based Hydrogen Oxidation Catalyst for Anion Exchange Membrane Fuel Cells

“…Over the past years, substantial progress has been made to develop CO-resistant catalysts for PEMFCs. − However, efforts toward the exploration of catalysts that are not sensitive to NH 3 poisoning have been sparse, although a trace amount of NH 3 in the H 2 feed can severely deteriorate the fuel-cell performances . In view of its considerable poisoning effect, NH 3 impurity in H 2 was set to be 0.1 ppm by the International Organization for Standardization for fuel cells, half of that for CO (0.2 ppm) .…”

“…24−26 However, efforts toward the exploration of catalysts that are not sensitive to NH 3 poisoning have been sparse, although a trace amount of NH 3 in the H 2 feed can severely deteriorate the fuel-cell performances. 27 In view of its considerable poisoning effect, NH 3 impurity in H 2 was set to be 0.1 ppm by the International Organization for Standardization for fuel cells, half of that for CO (0.2 ppm). 6 Thus, developing HOR catalysts that allow the use of H 2 with high concentrations of NH 3 will greatly reduce the purification cost.…”

A Mini-Review on NH3 Separation Technologies: Recent Advances and Future Directions

“…If the H 2 is injected into fuel cells, even a ppm level of NH 3 residue may poison the electrocatalysts and proton exchange membranes. 11 So far, many technologies such as physical condensation, 10 liquid absorption, 12 solid adsorption, 13 and membrane separation 14 the Harber−Bosch process. Liquid absorption utilizes the different solubilities of gases in liquid solvents to achieve the separation of NH 3 .…”

“…If the H 2 is used for combustion, the presence of residual NH 3 and N 2 may affect the caloric value. If the H 2 is injected into fuel cells, even a ppm level of NH 3 residue may poison the electrocatalysts and proton exchange membranes …”

High temperature polymer electrolyte membrane fuel cell degradation provoked by ammonia as ambient air contaminant

“…We recently investigated the platinum contamination by NH4H2PO4 using rotating ring disk electrodes and phosphoric acid electrolyte at room temperature and compared the results with the HT-PEM single cell operation for 500 h using 10 ppm of NH3 contamination in air flow, which present the basis of this study here. [36] Decrease of ORR activity and a changed ORR mechanism from 4-electron to 2-electron pathway by adsorbed nitrogen species was shown and discussed as one reason for the dramatic loss of HT-PEMFC performance. [36] In frame of presenting µ-computed tomography (µ-CT) as visualizing tool for degradation phenomena, we recently showed an increased porosity of bipolar plates caused by presence of SO2 during HT-PEMFC operation.…”