合成气制备乙醇Rh-Mn/SiO_2催化剂中活性金属表面结构的表征研究

采用原位EPR ,TPSR和NMR等表征手段研究了乙醇合成催化剂Rh Mn/SiO2 的性质 ,结果表明 ,活性金属铑及锰经浸渍法担载于载体上后即与表面羟基作用使金属固定在氧化硅的表面上 ,保证了高度分散活性金属的稳定性 ;高度分散中的铑锰相互结合 ,构成了乙醇合成中的高活性位 ;

The development of MOFs-based nanomaterials in heterogeneous organocatalysis

Metal-organic framework(MOF) is a class of inorganic-organic hybrid material assembled periodically with metal ions and organic ligands. MOFs have always been the focuses in a variety of frontier fields owing to the advantageous properties, such as large BET surface areas, tunable porosity and easyfunctionalized surface structure. Among the various application areas, catalysis is one of the earliest application fields of MOFs-based materials and is one of the fastest-growing topics. In this review, the main roles of MOFs in heterogeneous organocatalysis have been systematically summarized, including used as support materials(or hosts), independent catalysts, and sacrificial templates. Moreover, the application prospects of MOFs in photocatalysis and electrocatalysis frontiers were also mentioned.Finally, the key issues that should be conquered in future were briefly sketched in the final parts of each item. We hope our perspectives could be beneficial for the readers to better understand these topics and issues, and could also provide a direction for the future exploration of some novel types of MOFs-based nanocatalysts with stable structures and functions for heterogeneous catalysis.

Durable, superhydrophobic, antireflection, and low haze glass surfaces using scalable metal dewetting nanostructuring

In this paper we report a multifunctional nanostructured surface on glass that, for the first time, combines a wide range of optical, wetting and durability properties, including low omnidirectional reflectivity, low haze, high transmission, superhydrophobicity, oleophobicity, and high mechanical resistance. Nanostructures have been fabricated on a glass surface by reactive ion etching through a nanomask, which is formed by dewetting ultrathin metal films （〈 10 nm thickness） subjected to rapid thermal annealing （RTA）. The nanostructures strongly reduce the initial surface reflectivity （-4%）, to less than 0.4% in the 390--800 nm wavelength range while keeping the haze at low values （〈 0.9%）. The corresponding water contact angle （0c） is -24.5~, while that on a flat surface is -43.5~. The hydrophilic wetting nanostructure can be changed into a superhydrophobic and oleophobic surface by applying a fluorosilane coating, which achieves contact angles for water and oil of -156.3~ and -116.2~, respectively. The multicomponent composition of the substrate （Coming~ glass） enables ion exchange through the surface, so that the nanopillars＇ mechanical robustness increases, as is demonstrated by the negligible changes in surface morphology and optical performance after 5,000-run wipe test. The geometry of the nanoparticles forming the nanomask depends on the metal material, initial metal thickness and RTA parameters. In particular we show that by simply changing the initial thickness of continuous Cu films we can tailor the metal nanoparticles＇ surface density and size. The developed surface nanostructuring does not require expensive lithography, thus it can be controlled and implemented on an industrial scale, which is crucial for applications.

New progress of plasmonics in complex metal nanostructures

Noble metal nanostructures possess novel optical properties because of their collective electronic oscillations, known as sur- face plasmons （SPs）. The resonance of SPs strongly depends on the material, surrounding environment, as well as the geome- try of the nanostructures. Complex metal nanostructures have attracted research interest because of the degree of freedom in tailoring the plasmonic properties for more advanced applications that are unattainable by simple ones. In this review, we dis- cuss the plasmonic properties of several typical types of complex metal nanostructures, that is, electromagnefically coupled nanoparticles （NPs）, NPs/metal films, NPs/nanowires （NWs）, NWs/NWs, and metal nanostructures supported or coated by di- electrics. The electromagnetic field enhancement and surface-enhanced Raman scattering applications are mainly discussed in the NPs systems where localized SPs have a key role. Propagating surface plasmon polaritons and relevant applications in plasmonic routers and logic gates using NWs network are also reviewed. The effect of dielectric substrates and surroundings of metal nanostructures to the plasmonic properties is also discussed.

Surface plasmon-enhanced photochemical reactions on noble metal nanostructures

Nanoscale noble metals can exhibit excellent photochemical and photophysical properties, due to surface plasmon resonance(SPR) from specifically collective electronic excitations on these metal surfaces. The SPR effect triggers many new surface processes, including radiation and radiationless relaxations. As for the radiation process, the SPR effect causes the significant focus of light and enormous enhancement of the local surface optical electric field, as observed in surface-enhanced Raman spectroscopy(SERS) with very high detection sensitivity(to the single-molecule level). SERS is used to identify surface species and characterize molecular structures and chemical reactions. For the radiationless process, the SPR effect can generate hot carriers, such as hot electrons and hot holes, which can induce and enhance surface chemical reactions. Here, we review our recent work and related literature on surface catalytic-coupling reactions of aromatic amines and aromatic nitro compounds on nanostructured noble metal surfaces. Such reactions are a type of novel surface plasmon-enhanced chemical reaction. They could be simultaneously characterized by SERS when the SERS signals are assigned. By combining the density functional theory(DFT) calculations and SERS experimental spectra, our results indicate the possible pathways of the surface plasmonenhanced photochemical reactions on nanostructures of noble metals. To construct a stable and sustainable system in the conversion process of the light energy to the chemical energy on nanoscale metal surfaces, it is necessary to simultaneously consider the hot electrons and the hot holes as a whole chemical reaction system.