Anyuan Yin

Highly stable and efficient Ag/AgCl@TiO2 photocatalyst: preparation, characterization, and application in the treatment of aqueous hazardous pollutants.

A new plasmonic photocatalyst of Ag-AgCl@TiO(2) was prepared by deposition-precipitation and photoreduction. This photocatalyst exhibited efficient photocatalytic activity for the degradation of 4-chlorophenol and photoreduction of Cr(VI) ion under visible light irradiation. Its high photocatalytic activity can be attributed to the surface plasmon resonance effect of Ag nanoparticles, which were highly dispersed on the surface of Ag-AgCl@TiO(2). N(2) adsorption and desorption isotherm spectra, X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy were used to determine the correlation between the micro-structure and the catalytic properties of the as-prepared photocatalysts.

The synthesis of propylene glycol and ethylene glycol from glycerol using Raney Ni as a versatile catalyst

A new energy-efficient and atom-economical catalytic route for the direct catalytic synthesis of propylene glycol and ethylene glycol from glycerol under milder reaction conditions is presented. The one-pot aqueous-phase process is based on Raney Ni as a versatile catalyst.

High activity and selectivity of Ag/SiO2 catalyst for hydrogenation of dimethyl oxalate

Ag/SiO(2) prepared by a sol-gel process is highly effective for selective gas-phase hydrogenation of dimethyl oxalate to corresponding alcohols. The catalysts are of great potential as industrially viable and novel catalysts for the production of methyl glycolate and ethylene glycol.

Ion-Exchange Temperature Effect on Cu/HMS Catalysts for the Hydrogenation of Dimethyl Oxalate to Ethylene Glycol

A series of Cu/HMS (HMS=hexagonal mesoporous silica) catalysts, synthesized by ion exchange at temperatures from 303 to 363 K, are extensively investigated as catalysts for the hydrogenation of dimethyl oxalate to ethylene glycol. The physicochemical properties and catalytic activity are compared with those of a catalyst prepared by the conventional impregnation method. Characterization of the Cu/HMS catalysts shows that the surface and textural structure of the HMS support as well as the dispersion and nature of copper species depend strongly on the ion‐exchange temperature. Temperature‐programmed reduction patterns reveal the presence of three types of copper species. N2O titration experiments show that the catalyst prepared by ion‐exchange treatment at 333 K has the highest metallic copper surface area. A 98 % ethylene glycol yield is attained over the catalyst ion‐exchanged at 333 K, illustrating that an optimum ion‐exchange temperature is beneficial for the generation of copper catalysts with enhanced activity.

Remarkable Improvement of Catalytic Performance for a New Cobalt‐Decorated Cu/HMS Catalyst in the Hydrogenation of Dimethyloxalate

The synthesis of high-value-added fine chemicals from petroleum is of great academic and industrial significance. However, because of the long-term shortage and increased price of crude oil, syngas, which is derived from coal or biomass and owns advantages such as renewable, abundant, and environmentally friendly, is now arousing great interest. Syngas could be used to synthesize various chemicals and one such successful application is in the synthesis of dimethyloxalate (DMO), which was industrialized in the 1970s. The further hydrogenation of DMO will yield ethylene glycol (EG) or EtOH, the latter of which is an important fuel additive. Thus, the exploration of the manufacture of EG by the hydrogenation of DMO seems to be a promising and commercially viable alternative process to the petroleum approach. Among all of the available catalysts that convert DMO into EG, Cu/SiO2 catalysts exhibit high yields of EG and, hence, have been studied extensively. However, deactivation usually occurs when these working catalysts operate at a high liquid hourly space velocity (LHSV), which has drastically restricted their industrial application. To the best of our knowledge, of the currently available catalysts for the hydrogenation of DMO into EG, the maximum reported LHSV with 100 % yield of EG is 1.4 h 1 for a Cu/Al-HMS catalyst. Thus, to design a catalyst that operates at relatively high working LHSV is indispensable for improving the efficiency of EG or EtOH production, which can further improve the utilization of the downstream C1 or biomass products. Cobalt nanoparticles with a high capability for hydrogen dissociation have been widely used in hydrogenation reactions, such as the Fischer–Tropsch reaction, the hydrogenation of aromatic compounds, and the selective hydrogenation of aldehydes. As an additive, Bishop and coworkers reported a spectacular size-dependent effect caused by cobalt decoration, which led to a remarkable enhancement for C=O hydrogenation. Cobalt decoration also caused an electronic improvement in the cobalt-doped alloy. The catalytic activity in the hydrogenation of CO2 was greatly enhanced because of the formation of the Rh Co alloy in the Co-doped Rh/ SiO2 catalyst. [8] Herein, we fabricated a cobalt-decorated Cu/HMS catalyst with only 1 wt. % cobalt loading and observed a remarkable enhancement in its catalytic performance. The catalyst that was synthesized by a Co Cu co-ammonia-evaporation method afforded 100 % yield of EG, even at a relatively high LHSV. After 150 h of time on stream, with a LHSV of 1.2 h , both the conversion and the selectivity remained unchanged. However, the Cu/HMS catalyst without cobalt decoration showed a relatively low conversion of DMO and selectivity for EG (see the Supporting Information, Figure S1). Cobalt-decorated Cu/HMS catalysts with different orders of cobalt loading were synthesized according to a facile ammonia-evaporation (AE) method; all of the catalysts contained 10 wt. % Cu and 1 wt. % Co. In the “post-load” catalyst, the 1 wt. % of cobalt was deposited onto the Cu/HMS precursor, whereas, in the “pre-load” catalyst, the 10 wt. % of copper was loaded onto the 1 wt. % Co/HMS. The “co-load” catalyst was synthesized according to a Co Cu co-ammonia-evaporation method. The Cu/HMS and 1 wt. % Co/HMS catalysts were also synthesized for comparison. Before the activity test, all of the catalysts underwent an activation process with pure hydrogen at 573 K for 4 h. EG was synthesized by the hydrogenation of DMO through methyl glycolate (MG) with the formation of EtOH and 1,2-butanediol (1,2-BDO) as side-products (Scheme 1). Figure 1 shows

Nanocasting of CuAu alloy nanoparticles for methyl glycolate synthesis

CuAu/HMS alloy nanoparticles constructed viaammonia-evaporation–deposition–precipitation were prepared and exhibited excellent performance in methyl glycolate synthesis.

Synthesis of ZnO nanoflowers and their wettabilities and photocatalytic properties

By combing laser direct writing and hydrothermal growth, we demonstrate the growth of three-dimensional flowerlike ZnO nanostructures from aqueous solution. Our approach offers synthetic flexibility in controlling film architecture, coating texture and crystallite size. The wettability is studied by measurement of time-dependent contact angles in the as-grown samples. In addition, superior photocatalytic activity of the flowerlike ZnO nanostructures in the degradation of Rhodamine B is investigated as well. The influence factors and formation mechanism of the flowerlike ZnO nanostructures are also analyzed and discussed.