Xinlin Hong

Hydrazine-Assisted Liquid Exfoliation of MoS2 for Catalytic Hydrodeoxygenation of 4-Methylphenol.

A simple but effective method to exfoliate bulk MoS2 in a range of solvents is presented for the preparation of colloid flakes consisted of one to a few molecular layers by application of ultrasonic treatment in N2 H4 . Their high yield in solution and exposure of more active surface sites allows the synthesis of corresponding solid catalysts with remarkably high activity in hydrodeoxygenation of 4-methylphenol and this method can also be applied to other two dimensional materials.

Palladium on iron oxide nanoparticles: the morphological effect of the support in glycerol hydrogenolysis

Palladium supported on different shaped iron oxides has been synthesized and tested in glycerol hydrogenolysis in order to investigate the morphological effect of the support on catalytic performance. The plate-like iron oxide support exhibits a much higher activity due to the presence of more basic sites (oxygen vacancies) on its predominant polar surface. Thus, by tailoring the shape of the crystallized support, we show that bifunctional metal-oxide catalysis at the interface, like in the present example, can be significantly manipulated.

Temperature and solvent-dependent morphological sol gel transformation: an in situ microscopic observation.

A thermoreversible self-assemble process from gel (fiber) to sol (vesicle) state in the system alkylamine-ethylene glycol is for the first time monitored by in situ polarized optical microscopy, XRD, (1)H NMR, SEM, SAXRD, FTIR and drop shape analysis. It is found that the solvent molecules are intercalated with alkylamine molecules to form the organogel and vesicle structures. A model based on structural transformation with respect to these alkylamine gelator-solvent assembles is therefore proposed.

A promising low pressure methanol synthesis route from CO2 hydrogenation over Pd@Zn core–shell catalysts

At present, there is no low pressure methanol synthesis from CO2/H2 with high yield despite the presence of an upstream process of aqueous phase reforming (APR) of biomass derivatives on an industrial scale for CO2/H2 production at ca. 2 MPa. This is due to the intrinsic thermodynamics of the system which leads to particularly high CO levels at low pressure through reversed water gas shift reaction (RWGS) for most studied catalysts. Here we report a new Pd@Zn core–shell catalyst that offers a significantly higher kinetic barrier to CO/H2O formation in CO2 hydrogenation to reduce the CO levels but facilitates CH3OH formation at or below 2 MPa with CH3OH selectivity maintained at ca. 70% compared to ca. 10% over industrial Cu catalysts. The corresponding methanol yield at 2 MPa reaches 6.1 gmethanol gactive metal−1 h−1, which is comparable to the best reported value among a wide variety of catalysts under 5 MPa. It is thus believed that this active Pd based catalyst opens up a promising possibility for low pressure and temperature methanol production using a renewable biomass resource for fossil-fuel-starved countries.

Thermoreversible organogels formed in a polyol system for the preparation of Sn nanoparticles encapsulated in carbon

Here, we report, for the first time, the formation of a new thermoreversible organogel based on self-assembly of oleic acid (OA) and hexadecylamine (HDA) in ethylene glycol (EG) with addition of NaOH; this gelator can act as a template and carbon source for synthesis of Sn nanoparticles encapsulated in carbon.

A tunable metal–polyaniline interface for efficient carbon dioxide electro-reduction to formic acid and methanol in aqueous solution

It is reported that metals on polyaniline (PANI) prepared by a simple method can exhibit excellent activity in the electro-reduction of CO2 to HCOOH or CH3OH due to tunable properties: N atoms on PANI capture CO2 through a strong Lewis acid-base interaction while Pd atoms, amongst Pd, Pt, and Cu studied, facilitate the fastest proton and electron transfers along PANI to the CO2 trapped sites to give rise to the best HCOOH yield in a highly cooperative manner.

Morphology effect of polythiophene catalysts on photo-degradation of methylene blue

Polythiophene (PTh) nanosheets and spheres were successfully synthesized by changing the oxidation ability of ferric ions without any templates. Their distinct morphologies caused by different growth processes lead to different photo-catalytic activity for methylene blue (MB) degradation under visible light. The mechanism of morphology–performance relationship was thoroughly studied. It shows that different morphologies are the reflection of different length and bond-connection of PTh chains, which are the real reasons for different performance.

Probing the Size and Shape Effects of Cubic‐ and Spherical‐Shaped Palladium Nanoparticles in the Electrooxidation of Formic Acid

A systematic study of size and shape effects in the electrooxidation of formic acid over our controlled synthesized Pd nanospheres and nanocubes as material models by using infrared spectroscopy and density functional calculations was undertaken. The bridge formate intermediate on the metal terrace was identified as the main contributor to the electrooxidation activity of formic acid, whereas linear formate with much weaker adsorption energy was unstable and could not proceed to the product. It was also demonstrated that Pd(1 0 0) cubes could stabilize two bridge formate species, and thus, they show higher electrooxidation activity than Pd spheres at comparable sizes.

Photo and electronic excitation for low temperature catalysis over metal nanoparticles using an organic semiconductor

Simple supported metal catalysts are active for the destruction of a wide range of hazardous chemicals of environmental concerns, including CO, N2O and volatile organic compounds (VOCs), in air at elevated temperatures. However, they are severely restricted because of unfavourable enthalpy and intrinsic low activity under ambient conditions, in particular the inapplicability of using high temperatures in confined spaces. Here, we report a simple but significant means of electron promotion to metal nanoparticles by the use of an organic polythiophene as a support or support supplement, which gives rise to an active modified metal surface for selective catalysis at low temperatures with light or electromotive excitation. It is observed that the finite size of electronic structure of dispersed metal nanoparticles can be influenced by the conjugative bands of a polymer, which leads to the modification of its adsorptive properties. This renders the composite material active for a number of oxidation and decomposition reactions under ambient conditions, which outperforms the conventional catalysts. As a result, the present study forms a basis for further developments in the design and engineering of a new class of greener plastic nanocatalysts with facilitated electron promotion to metal catalysts for environmentally relevant chemical transformations.

Transparent superhydrophobic hollow films (TSHFs) with superior thermal stability and moisture resistance

Highly transparent superhydrophobic hollow films (contact angle, 165.7° and sliding angle, 2.1°) have been prepared by using candle soot as a template, followed by methyltrimethoxysilane (MTMS) chemical vapor depostion (CVD) and calcination at 450 °C, without the addition of dibutyl tin laurate (DBTL). The influence of deposition time on the superhydrophobicity and transparency of the as-prepared films was discussed herein to get the optimum performance film. The film shows high transparency (transmittance close to 90%) when it was coated on a glass substrate. What is more, it shows good thermal stability and superior moisture resistance as well, retaining its superhydrophobicity after calcining up to 500 °C or even exposure to ambient conditions for 30 days. 29Si NMR, XPS spectra and thermal analysis verify the existence of methyl groups linked with silicon matrix on film (low surface energy), while AFM and TEM analysis confirm the sub-100 nm roughness and hollow structure of the optimum film.