SBIR Phase I: Fluorine-free membranes for PEM electrolyzers
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Engineering topics
Publications and source records attributed to Yang, Hongzhou.
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Electrochemical CO2 reduction reaction (CO2RR) to produce formic acid has attracted great interest recently since formic acid can be used as a feedstock for biorefineries. Over the past decade, much effort has been devoted to the prospects of electrochemical CO2 conversion to formic acid. However, issues including low current density, low selectivity, low energy efficiency, poor long-term stability, and production of formate salts instead of formic acid remain as the great challenges for the development and commercialization of this technology. Recently, Dioxide Materials (DM) has developed an electrolyzer technology that can directly convert CO2 to pure formic acid with a three-compartment CO2 electrolyzer. In this work, DM will present our recent effort on improving the electrolyzer performance operating at industry relevant current density (200 mA/cm2). We have demonstrated 200 mA/cm² with 80% Faradaic efficiency for 1000 hours of operation. The effects of CO2 concentration and impurities in the flue gas on the electrolyzer performance will be discussed, as will ongoing efforts to test the device at a coal fired power plant. The long-term (1000 h) performance of the electrolyzer will also be presented.
Formic acid (FA) is an industrial chemical. It is used as a preservative for silage, as a digestive aid for animals, as a fluid for fracking, as a pharmaceutical intermediate and in leather tanning. The global formic acid market is valued at 777.4 million USD in 2020 and is expected to reach 851.8 million USD by the end of 2026. A new major formic acid application is the use of formic acid as a key feedstock for the bioprocessing industry. It has the potential to grow tremendously if we can lower the cost of formic acid production compared with the current fossil-fuel one. Recently, Dioxide Materials has developed a technology that can directly convert CO 2 to pure formic acid with a three-compartment CO 2 electrolyzer. However, the electrolyzer performance needs further improvement for the technology to be commercially viable. The major objective of this project is to develop the electrolyzer technology to enable formic acid as a feedstock for the bioprocessing industry to be economically manufactured from flue gas from a coal fired pilot plant. In particular, the project is to understand how to run the electrolyzer for the conversion of CO 2 into formic acid using flue gas from a coal fired power plant as a source of CO 2 . The work will include characterizing how the performance of the electrolyzer changes with low CO 2 concentration and impurities, developing new cell designs that can still operate with feedstocks with low CO 2 concentrations, testing simulated flue gas in the electrolyzer system and developing filters to remove any impurities that arise.
The electrochemical conversion of carbon dioxide (CO2) into valuable fuels and feedstocks has gained great attention recently due to the global urgency to mitigate the rapid climate change. A wide variety of chemicals can be obtained through the electrochemical CO2 reduction reaction (CO2RR). Among all the chemicals generated through CO2RR, formic acid has attracted great interest because of its wide applications in silage preservation in agriculture, as an antibacterial agent in animal food additives, as a chemical additive in leather and tanning processing, as a chemical component in textile dyeing and finishing, as a reagent in pharmaceutical and chemical synthesis, and as deicing agents and a component in drilling fluids. Recently, the use of formic acid as a feedstock for biorefineries has also attracted increasing interest.
Electrochemical conversion of CO 2 to useful products at temperatures below 100 °C are nearing the commercial scale. Pilot units for CO 2 conversion to CO are already in testing. Units to convert CO 2 to formic acid are projected to reach pilot scale in the next year. Further, several investigators are starting to observe industrially relevant rates of the electrochemical conversion of CO 2 conversion to ethanol and ethylene with the needed hydrogen coming from water. In each case, Faradaic efficiencies of 80% or more and currents above 200 mA/cm –2 can be reproducibly achieved. In this study we describe the key advances in nano catalysts that lead to the impressive performance, indicate where additional work is needed and provide benchmarks that others can use to compare their results.
The electrochemical reduction of CO 2 to formate and formic acid has attracted a great amount of academic and commercial interest over the past five years. A number of experimental studies have generated data on the Faradaic performance and stability of various candidate catalyst materials in producing formate or formic acid. However, most of the data has been conducted at low current densities and over short time periods, typically hours to days. There is a critical need in providing long-term catalyst stability as well as electrolyzer-based operating data, which are needed for the commercial scale-up and operation of this technology, especially at high current densities. In this paper, the electrochemical CO 2 conversion to pure formic acid was conducted using a three-compartment design electrolyzer, demonstrating electrolyzer catalyst and performance stability for over 1000 h at current densities up to 200 mA cm -2 . Depending on the operation conditions, the electrolyzer directly produced a 6.03 to 12.92 wt% (1.3 to 2.8 M) formic acid product at Faradaic efficiencies ranging between 73.0 to 91.3%. Data on electrolyzer performance, including formic acid product generation rate, energy efficiency, and energy consumption are reported at three different current densities, 100, 200, and 250 mA cm -2 . Finally, a long term 1000 h electrolyzer stability run at 200 mA cm -2 is presented, providing information on the operating conditions required in obtaining stable electrolyzer performance. All the data will be extremely useful in the commercial scale-up of this technology.