echemi logo
Product
  • Product
  • Supplier
  • Inquiry
    Home > Science: dynamic polynuclear sites formed by copper ions in NOx SCR reaction

    Science: dynamic polynuclear sites formed by copper ions in NOx SCR reaction

    • Last Update: 2017-09-03
    • Source: Internet
    • Author: User
    Search more information of high quality chemicals, good prices and reliable suppliers, visit www.echemi.com
    Susannah Scott, a chemist at the University of California, Santa Barbara, said that there is no modern chemistry without catalyst The catalyst is very powerful It is not only the condition of chemical reaction, but also the direction and way of chemical reaction 90% of the modern chemical industry is inseparable from catalyst, which is particularly important in the production process of pharmaceutical, energy and pesticide fields So far, about 15 Nobel Prize in chemistry have been awarded to catalysis researchers, and thousands of chemists are engaged in catalysis research in the world The charm of catalytic research is that people's understanding of the reaction mechanism is always in-depth, so many seemingly very old topics can always be rejuvenated For example, Cu / ZnO / Al2O3 catalyzes the synthesis of methanol, oxidative dehydrogenation of propane and selective catalytic reduction (SCR) of NOx Low temperature SCR catalytic cycle (source: Science) NOx SCR reaction refers to the selective reaction of reducing agent (such as liquid ammonia and urea) with NOx in flue gas to generate nitrogen and water under the action of catalyst The reaction was first discovered by Engelhard company of the United States and applied for patent in 1957 Later, driven by the environmental protection policy of Japan, V2O5 / TiO2 catalyst was successfully developed, which is now widely used In 1977 and 1979, V2O5 / TiO2 catalyst was successfully used in oil and coal-fired boilers SCR technology is very effective and mature in the control of boiler flue gas NOx, and has become the most widely used and most effective flue gas denitrification technology in the world The dependence of Cu density on SCR rate (source: Science) recently, science published an article entitled "dynamic multiple sites formed by mobile coppers in NOx selective quantitative reduction" by William F Schneider and rajamani gounder of Purdue University The team used Cha molecular sieve of Cu ion exchange as catalyst and NH3 as reducing agent to carry out SCR reaction of NOx It was found that at low temperature (< 523K), the catalytic activity was directly related to the bulk density of Cu ion, so it was proposed that Cu Cha was not a unit point reaction in SCR reaction of NOx The simulation of diffusion range of Cu (NH3) 2 (source: Science) researchers combined with steady-state and transient dynamics tests, X-ray absorption spectroscopy (XAS) and the first principle calculation confirmed that the moving Cu ions can form transient ion pairs through zeolite pores, which involves the integration of the oxidation-reduction step of Cui → CuII mediated by O2 and the selective catalytic reduction step Electrostatic binding to the Al center of the framework limits the amount of each ion that can be detected, thus limiting the ability to form ion pairs The dynamic and reversible formation of single atom polynuclear sites shows an interesting phenomenon: polynuclear sites fall outside the normal limits of heterogeneous or homogeneous catalysts This phenomenon is different from the traditional heterogeneous and homogeneous catalysis, which provides a new way for people to design advanced catalysts Paper link: http://science.sciencemag.org/content/357/6354/898
    This article is an English version of an article which is originally in the Chinese language on echemi.com and is provided for information purposes only. This website makes no representation or warranty of any kind, either expressed or implied, as to the accuracy, completeness ownership or reliability of the article or any translations thereof. If you have any concerns or complaints relating to the article, please send an email, providing a detailed description of the concern or complaint, to service@echemi.com. A staff member will contact you within 5 working days. Once verified, infringing content will be removed immediately.

    Contact Us

    The source of this page with content of products and services is from Internet, which doesn't represent ECHEMI's opinion. If you have any queries, please write to service@echemi.com. It will be replied within 5 days.

    Moreover, if you find any instances of plagiarism from the page, please send email to service@echemi.com with relevant evidence.