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Innovation Program of Science and Research from the Dalian Institute of Chemical Physics[DICP TMSR201601]
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Artificial Photosynthesis Project of the New Energy and Industrial Technology Development Organization (NEDO)
No full textOperando dual beam FTIR spectroscopy unravels the promotional effect of Zn on HZSM-5 in iso-butane aromatization
No full textAlthough zinc-promoted HZSM-5 catalysts have been widely used in the aromatization of short-chain hydrocarbons, the precise role of Zn in catalysis is still unclear due to the complex reaction mechanism and the lack of in situ or operando techniques. A home-built dual beam Fourier transform infrared (DB-FTIR) spectrometer, designed to eliminate the interference of gas-phase molecular vibration and heat irradiation through collecting reference and sample spectra simultaneously, can present an unimpeded view of the dynamic surface processes involved in gas/solid heterogeneous catalysis under real reaction conditions. With the aid of the DB-FTIR spectrometer, we directly observed the reaction process of iso-butane aromatization over HZSM-5 and Zn/HZSM-5. Unlike conventional studies, the aromatization was firstly performed under sub-atmospheric pressures using a home-built fixed-bed reactor. Comprehensive characterization results demonstrate that, besides their good dehydrogenation abilities, Zn species undergo strong interactions with olefin intermediates, even at sub-atmospheric pressures, but weaker interaction (or adsorption) with final aromatic products. Density functional theory studies certify that strong interactions could inhibit the desorption of olefin intermediates, which is beneficial for secondary chain-growth reactions relating to aromatics
Carbon-supported ultrafine Pt nanoparticles modified with trace amounts of cobalt as enhanced oxygen reduction reaction catalysts for proton exchange membrane fuel cells
No full textTo accelerate the kinetics of the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells, ultrafine Pt nanoparticles modified with trace amounts of cobalt were fabricated and decorated on carbon black through a strategy involving modified glycol reduction and chemical etching. The obtained Pt36Co/C catalyst exhibits a much larger electrochemical surface area (ECSA) and an improved ORR electrocatalytic activity compared to commercial Pt/C. Moreover, an electrode prepared with Pt36Co/C was further evaluated under H-2-air single cell test conditions, and exhibited a maximum specific power density of 10.27 W mg(pt)(-1),which is 1.61 times higher than that of a conventional Pt/C electrode and also competitive with most state-of-the-art Pt -based architectures. In addition, the changes in ECSA, power density, and reacting resistance during the accelerated degradation process further demonstrate the enhanced durability of the Pt36Co/C electrode. The superior performance observed in this work can be attributed to the synergy between the ultrasmall size and homogeneous distribution of catalyst nanoparticles, bimetallic ligand and electronic effects, and the dissolution of unstable Co with the rearrangement of surface structure brought about by acid etching. Furthermore, the accessible raw materials and simplified operating procedures involved in the fabrication process would result in great cost-effectiveness for practical applications of PEMFCs. (C) 2019, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved
