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排序方式: 共有107条查询结果,搜索用时 8 毫秒
101.
Pei Jing Tao Gan Hui Qi Bin Zheng Xuefeng Chu Guiyang Yu Wenfu Yan Yongcun Zou Wenxiang Zhang Gang Liu 《催化学报》2019,40(2):214-222
An efficient and low-cost supported Pt catalyst for hydrogenation of niroarenes was prepared with colloid Pt precursors and α-Fe2O3 as a support. The catalyst with Pt content as low as 0.2 wt% exhibits high activities, chemoselectivities and stability in the hydrogenation of nitrobenzene and a variety of niroarenes. The conversion of nitrobenzene can reach 3170 molconv h?1 molPt?1 under mild conditions (30 °C, 5 bar), which is much higher than that of commercial Pt/C catalyst and many reported catalysts under similar reaction conditions. The spatial separation of the active sites for H2 dissociation and hydrogenation should be responsible for the high chemoselectivity, which decreases the contact possibility between the reducible groups of nitroarenes and Pt nanoparticles. The unique surface properties of α-Fe2O3 play an important role in the reaction process. It provides active sites for hydrogen spillover and reactant adsorption, and ultimately completes the hydrogenation of the nitro group on the catalyst surface. 相似文献
102.
Qian X Tong X Wu Q He Z Cao F Yan W 《Dalton transactions (Cambridge, England : 2003)》2012,41(33):9897-9900
A new solid high-proton conductor, substituted heteropoly acid with Dawson structure H(7)[In(H(2)O)P(2)W(17)O(61)]·23H(2)O, has been synthesized by the degradation/ion exchange/freezing method. The pH of the synthesis reaction was given. The product was characterized by chemical analysis, IR, UV, XRD and TG-DTA. The determination of conductivity shows that H(7)[In(H(2)O)P(2)W(17)O(61)]·23H(2)O is an excellent solid high-proton conductor with conductivity of 1.34 × 10(-3) S cm(-1) at 18 °C, and 70% relative humidity (RH). Its activation energy is 37.72 kJ mol(-1), which suggests that its mechanism of proton conduction is the Vehicle mechanism. 相似文献
103.
Kui Fan Zhenhua Li Yingjie Song Wenfu Xie Mingfei Shao Min Wei 《Advanced functional materials》2021,31(10):2008064
Highly efficient and low-cost electrodes have a key role in the development of advanced energy devices such as fuel cells and metal–air batteries. However, electrode performance is typically limited by low utilization of active sites, which causes a considerable drop in energy density. To overcome this issue, a single-atom-containing integrated electrode is developed through a confinement synthesis strategy by using organic molecule-intercalated layered double hydroxides (LDHs) as precursors. The as-prepared integrated electrode has a well-defined nanosheet array structure with a homogeneous anchored single atomic Co catalyst and many exposed hierarchical pores. Moreover, the coordination environment of single atoms (Co N or Co S) is precisely controlled by regulating the type of interlayer molecules in the LDHs. Consequently, the optimized electrode exhibits high bifunctional activity toward both the oxygen reduction and oxygen evolution reactions. This electrode is directly assembled into an all-solid-state zinc–air battery that showed outstanding flexibility and long-term charge/discharge stability. Because of the versatility of LDH materials, it is expected that the proposed strategy can be extended to the construction of other integrated electrodes for high-performance energy storage and conversion devices. 相似文献
104.
Huayun Du Yinghui Wei Wanming Lin Lifeng Hou Zengqing Liu Yanli An Wenfu Yang 《Applied Surface Science》2009,255(20):8660-8666
A method of surface alloying treatment has been developed: Ni powders were welded into the surface of iron plates by Surface Mechanical Attrition Treatment (SMAT), followed by annealing at certain temperature for 30 min. A Ni-Fe alloy layer with thickness about 100 μm in the sample surface was fabricated on pure iron plate. Scanning electron microscope (SEM), glow discharge spectrum (GDS), and X-ray diffraction (XRD) methods were used to analyze the microstructure, the composition and the phases of the alloy layer. Studies on the interface microstructure indicated that there was significant atomic diffusion and formation of multilayer of intermetallic compound and solid solution in SMAT process. Subsequent annealing accelerates the alloying process. The corrosion test shows the sample by SMAT treated with Ni powders exhibit the best corrosion resistance. 相似文献
105.
106.
Wenfu Xie Yuke Song Shijin Li Jianbo Li Yusen Yang Wei Liu Mingfei Shao Min Wei 《Advanced functional materials》2019,29(50)
Single‐atomic electrocatalysts (SACs) have shown great promise in electrocatalysis fields owing to their theoretical maximum atom utilization (100%). Yet still, it is far from expectation in practical applications due to entrapping within supports and blocking by aggregation. Herein, self‐supported carbon nanosheet arrays consisting of single‐atomic Co electrocatalyst (SS‐Co‐SAC) toward oxygen‐involved reaction and zinc–air batteries are reported. Impressively, the as‐synthesized SS‐Co‐SAC gives a markedly enhanced utilization of active sites (≈22.3%@2.3 wt%) as a result of single‐atomic dispersion of Co within a unique nanosheet arrays architecture, which is the largest value among other reported results. Benefiting from the high utilization of active sites, the SS‐Co‐SAC electrode exhibits outstanding electrocatalytic performance for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Notably, the turnover frequency value for ORR is determined to be ≈9.26 s?1, which stands for the highest level among noble metal‐free electrocatalysts reported previously. Moreover, as an air‐cathode for zinc–air batteries with SS‐Co‐SAC, a power density of 195.1 mW cm?2 and a robust durability are achieved. It is believed that this study would guide the future design of highly active and durable single‐atom catalysts for both fundamental research and practical applications. 相似文献
107.