Abstract:Tolerance to small amounts of CO is important for proton exchange membrane fuel cells ͑PEMFCs͒ operating on hydrogen obtained by reforming carbon-based fuels. Platinum-based catalysts used today suffer high anode polarization losses, reducing performance and fuel efficiency. Here, findings in the search for CO-tolerant catalysts are reported. Novel platinum-based catalysts were discovered that show low polarization for oxidation of hydrogen containing 104 ppm CO, and little adsorbed CO was observed in CO strip… Show more
“…It is reported that the Pt catalyst used in hydrogen fuel cells is poisoned by the traces amounts of CO ($100 ppm) in H 2 . 40 Thus, the development of an effective single-stage LT-WGS process for high-purity H 2 production is a highly desirable but challenging task, which requires innovative catalytic materials and reaction processes. Pt-based catalysts are considered promising WGS catalysts because of their high low-temperature activity, especially when Pt dispersed on metal oxides with oxygen vacancies, such as CeO 2 and doped-CeO 2 supports.…”
Catalytic conversion of one-carbon (C1) molecules, such as CO, CO 2 , CH 4 , and CH 3 OH, into fuels and value-added chemicals is a vitally important process in the chemical industry because of its close correlation to energy and environmental implications. However, the selectivity control, energy saving, and emission reduction remain great challenges for C1 chemistry due to the complex and changeable conversion processes. Herein, we briefly summarize recent advances and milestones in conversion of C1 molecules in the last decade, particularly focusing on the new reaction processes, including thermal-driven reactions, such as direct methane to ethylene, CO 2 hydrogenation, and oxide-zeolite process for syngas conversion, and mild-condition conversion processes, such as roomtemperature methane conversion, electrochemical water-gas shift, electrocatalytic CO reduction to ethylene, and light-driven methanol to ethylene glycol. The challenges and prospects are also fully discussed toward the C1 chemistry for the basic and applied research in the future.
“…It is reported that the Pt catalyst used in hydrogen fuel cells is poisoned by the traces amounts of CO ($100 ppm) in H 2 . 40 Thus, the development of an effective single-stage LT-WGS process for high-purity H 2 production is a highly desirable but challenging task, which requires innovative catalytic materials and reaction processes. Pt-based catalysts are considered promising WGS catalysts because of their high low-temperature activity, especially when Pt dispersed on metal oxides with oxygen vacancies, such as CeO 2 and doped-CeO 2 supports.…”
Catalytic conversion of one-carbon (C1) molecules, such as CO, CO 2 , CH 4 , and CH 3 OH, into fuels and value-added chemicals is a vitally important process in the chemical industry because of its close correlation to energy and environmental implications. However, the selectivity control, energy saving, and emission reduction remain great challenges for C1 chemistry due to the complex and changeable conversion processes. Herein, we briefly summarize recent advances and milestones in conversion of C1 molecules in the last decade, particularly focusing on the new reaction processes, including thermal-driven reactions, such as direct methane to ethylene, CO 2 hydrogenation, and oxide-zeolite process for syngas conversion, and mild-condition conversion processes, such as roomtemperature methane conversion, electrochemical water-gas shift, electrocatalytic CO reduction to ethylene, and light-driven methanol to ethylene glycol. The challenges and prospects are also fully discussed toward the C1 chemistry for the basic and applied research in the future.
“…11 From the aspect of practical applications in the hydrogen fuel cells, catalysts for the WGS reaction with low working temperature, especially under 200 1C, are highly desirable because the low temperature can maintain low levels of CO so that the platinum electrode of hydrogen fuel cells is not poisoned. 12 Front runner catalysts in low-temperature WGS reactions are noble metals supported on reducible oxide substrates and alkali-promoted noble metals. 13,14 A remarkable breakthrough has been achieved in a recent experiment, in which the CO conversion employing a-MoC-supported Au layered clusters as a catalyst is at least one order of magnitude higher (close to 98% at 423 K) 15 than other known catalysts at the same temperature.…”
Water molecules linked by hydrogen bonds are responsible for the high efficiency of bi-functional catalysts for the water-gas-shift (WGS) reaction because water can act as a proton transfer medium. Herein,...
“…1) so as not to affect the downstream applications 13 . As an example, a trace amount of CO (around 100 ppm) in H 2 will seriously poison the Pt-based catalyst on the anode of proton exchange membrane fuel cell and reduce the performance significantly 14 . Therefore, the direct production of high purity hydrogen under mild conditions is more economical and eco-friendly but a challenging task, which requires innovative catalytic processes.Fig.…”
Traditional water–gas shift reaction provides one primary route for industrial production of clean-energy hydrogen. However, this process operates at high temperatures and pressures, and requires additional separation of H2 from products containing CO2, CH4 and residual CO. Herein, we report a room-temperature electrochemical water–gas shift process for direct production of high purity hydrogen (over 99.99%) with a faradaic efficiency of approximately 100%. Through rational design of anode structure to facilitate CO diffusion and PtCu catalyst to optimize CO adsorption, the anodic onset potential is lowered to almost 0 volts versus the reversible hydrogen electrode at room temperature and atmospheric pressure. The optimized PtCu catalyst achieves a current density of 70.0 mA cm−2 at 0.6 volts which is over 12 times that of commercial Pt/C (40 wt.%) catalyst, and remains stable for even more than 475 h. This study opens a new and promising route of producing high purity hydrogen.
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