Several lanthanum oxide-modified Cu/SiO 2 (La-Cu/SiO 2 ) catalysts synthesized by urea-assisted gelation and postimpregnation were used for the vapor-phase chemoselective hydrogenation of dimethyl oxalate (DMO) into ethylene glycol (EG). The 1.0La-Cu/SiO 2 -u catalyst with 1.0 wt % La loading was found to have the highest activity, whereas the catalyst with higher La loading at 3.0 wt % adversely affected the deterioration of catalytic activity. H 2 -TPR results revealed that strong interactions between La promoters and Cu species substantially changed catalyst reducibility and made some Cu 2+ species on catalyst precursors difficult to be reduced. Several positive variations induced by the introduction of La were confirmed by in situ XRD, N 2 O chemisorption, H 2 -TPD, X-ray Auger electron spectroscopy, and in situ FT-IR of chemisorbed CO. These variations included increased Cu metallic dispersion, improved ability for H 2 activation, elevated surface concentration of Cu + species, and enhanced stability of catalyst nanostructure. The formation of unique Cu−O−La bonds between LaO x and cupreous species located at interfacial sites was presumably responsible for the improved catalytic performance and stability of La-Cu/SiO 2 -u catalyst.

There has been an intense research to develop 2-H MoS2 based catalysts to reduce or eliminate the use of Pt/C at higher metal loading for hydrogen evolution reaction (HER) in catalytic hydrolysis of water, which enables the capture of renewable energy sources as fuel and chemical. However, the study of its uncommon polymorph, 1T-MoS2 and particularly the doping effect with transition metal (TM) is rather limited due to the instability of this phase. Here we report a simple ambient temperature modification method using sonication to dope the single layer 1T-S MoS2 with various TM precursors. It is found that 1-T S MoS2 is more superior than corresponding 2H-S MoS2 and the inclusion of 3 wt% Pt or Pd can also further enhance the HER activity. STEM-EELS and XAS show the active single TM atom doping on this surface is to account for the high activity. Kinetic and DFT analyses also illustrate that the metallic nature of 1T-S MoS2 greatly facilitates the first proton reduction step from water, rendering it non-rate limiting as contrast to that of 2H-S MoS2. The inclusion of TM single doper such as Pd, despite at low loading, can offer the dramatic acceleration on the rate limiting recombination of H to H2. As a result, a bifunctional catalysis for HER over this tailored composite structure is demonstrated which outperforms most reported catalysts in this area.

Bimetallic NiFe nanoparticles supported on carbon nanotubes (CNTs) were prepared and evaluated for catalytic hydrodeoxygenation (HDO) of guaiacol, which is a model ligninderived compound. Appropriate combination of Ni and Fe demonstrated high activity and significantly enhanced selectivity to cyclohexane and phenol, whereas monometallic Ni and Fe catalysts displayed poor activities or selectivities. The tunable selectivity of guaiacol HDO was found to be dependent on Ni/Fe atomic ratios. Cyclohexane and phenol are major products over the Ni5Fe1/CNT and Ni1Fe5/CNT catalysts, respectively. Characterization results confirmed that NiFe alloys were formed and elicited synergistic effects on the HDO performance. The selectivity-switchable performance of NiFe/CNT may be due to the synergism between Ni domains, where H2 could be easily activated, and Fe domains, which exhibited strong oxophilicity. Deactivation was observed over the monometallic catalyst which may be ascribed to the agglomeration of active nanoparticles. Metallic size effect on the HDO reaction was further investigated using monometallic Ni/CNT, Fe/CNT and bimetallic NiFe/CNT catalysts.

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An ordered mesoporous carbon (CMK-3)-supported gold catalyst was prepared and used in the aerobic oxidation of glucose to gluconic acid under base-free conditions with molecular oxygen. XRD and TEM results revealed that gold nanoparticles were uniformly dispersed on the surface and in the channels of CMK-3. Catalytic tests showed that conversion remarkably increased with decreased selectivity when oxygen pressure and reaction temperature were increased. Glucose conversion to gluconic acid reached over 92% with 85% selectivity under the conditions of 383 K reaction temperature, 0.3 MPa oxygen pressure, and 2 h reaction time. Hydrogen peroxide was generated during reaction, and the relationship between hydrogen peroxide and the byproduct fructose was discussed. Low glucose/Au molar ratio minimized fructose formation. A 92% gluconic acid yield was obtained after reaction for 15 min when the molar ratio of glucose/Au was set to 100. The spent catalyst treated with an aqueous solution of NaOH at 363 K could produce glucose conversion up to 87%, which was close to the result of as-prepared catalyst and excluded the effect of alkaline residues.