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As the most abundant polysaccharide in lignocellulosic biomass, a clean and renewable carbon resource, cellulose shows huge capacity and roused much attention on the methodologies of its conversion to downstream products, mainly including platform chemicals and fuel additives. Without appropriate treatments in the processes of cellulose decompose, there are some by-products that may not be chemically valuable or even truly harmful. Therefore, higher selectivity and more economical and greener processes would be favored and serve as criteria in a correlational study. Aqueous phase, an economically accessible and immensely potential reaction system, has been widely studied in the preparation of downstream products of cellulose. Accordingly, this mini-review aims at making a related summary about several conversion pathways of cellulose to target products in aqueous phase. Mainly, there are four categories about the conversion of cellulose to downstream products in the following: (i) cellulose hydrolysis hydrogenation to saccharides and sugar alcohols, like glucose, sorbitol, mannose, etc.; (ii) selective hydrogenolysis leads to the cleavage of the corresponding glucose C-C and C-O bond, like ethylene glycol (EG), 1,2-propylene glycol (PG), etc.; (iii) dehydration of fructose and further oxidation, like 5-hydroxymethylfurfural (HMF), 2,5-furandicarboxylic acid (FDCA), etc.; and (iv) production of liquid alkanes via hydrogenolysis and hydrodeoxygenation, like pentane, hexane, etc. The representative products were enumerated, and the mechanism and pathway of mentioned reaction are also summarized in a brief description. Ultimately, the remaining challenges and possible further research objects are proposed in perspective to provide researchers with a lucid research direction.

The development of efficient, stable, and low-cost catalytic material for the oxygen reduction reaction (ORR) is currently highly desirable but challenging. In this work, based on first-principles calculation, the stabilities, catalytic activities and catalytic mechanisms of isolated Au atom supported on defective porous BN (p-BN) have been studied in detail. The results reveal that the defective p-BN anchor Au atom strongly to ensure the stability of Au/p-BN. Based on frontier molecular orbital and charge-density analysis, isolated Au atom supported on porous BN with VN defect (Au/p-BN-VN) is an effective ORR catalyst. Especially, the low barriers of the formation (0.38 eV) and dissociation (0.31 eV) of *OOH and the instability of H2O2 on Au/p-BN-VN catalyst suggest that ORR proceeds via 4-electron pathway. Along the favorable pathway, the reduction of O2 to *OOH is the rate-limiting step with the largest activation barrier of 0.38 eV and the maximum free energy change is 1.88 eV. Our results provide a useful guidance for the design and fabrication of new Au-base catalyst with high-efficiency and are beneficial for the developing of novel isolated metal atom catalysts for ORR.

Abstract: Supported nickel catalysts for aqueous-phase catalytic hydrogenation/dehydration of furfural were prepared using impregnation method with different supporting materials. Effects of supporting materials, nickel loading and reaction temperature on conversion rate of furfural as well as selectivity for desired product C5 were systematically studied. Experiments showed that catalytic activity of Ni/SiO2–Al2O3 was obviously higher than that of Ni/γ-Al2O3. The conversion of furfural over 14wt.%Ni/SiO2–Al2O3 catalyst was 62.99% under the temperature of 140°C and the cold pressure of H2 3.0MPa, while that was 19.19% over 14wt.%Ni/γ-Al2O3 under the same conditions. Conversion rate of furfural increased with temperature, but selectivity for desired product decreased with temperature. Tentative reaction mechanisms of hydrogenation/dehydration were proposed. In order to investigate catalyst recyclability, a batch of Ni/SiO2–Al2O3 was reused three times and analyzed by Thermogravimetry (TG). It was found that considerable amount of coke formed on Ni/SiO2–Al2O3 surface and deteriorated its activity dramatically after second use. [Copyright &y& Elsevier]

The preparation of green and economical bio-aviation fuel is a priority for the sustainable development industry. In this study, Jatropha oil was used as a raw material to catalyze the conversion of raw material to aviation kerosene fraction by photothermal coupling under the conditions of light and low temperature. The correlations among conversion rate, target alkane selectivity, composition distribution, and catalyst microstructure were investigated by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), nitrogen (N2) adsorption and desorption, X-ray fluorescence (XRF), ammoniatemperature programmed desorption (NH3-TPD), ultraviolet-visible spectrophotometry (UV-Vis), and other characterization. The correlation between conversion and target alkane selectivity and composition distribution and catalyst microstructure was investigated, and different modification methods and different molecular sieve materials were selected. The results showed that the molecular sieves modified with the solid dispersion method could retain the structural stability of titanium dioxide (TiO2) and molecular sieves to a great extent while slightly enhancing the pore capacity and pore size of the catalyst to make it easier to adsorb reactants; the introduction of active metal platinum (Pt) could reduce the forbidden bandwidth of the catalyst, increase the weak acid amount of the catalyst, improve the adsorption capacity of hydrogen (H2), and thus improve the catalytic ability, resulting in a suitable catalyst for this study: P-21. The photothermal catalytic reaction of Jatropha oil using P-21 catalyst obtained 97.21% conversion and 74.99% selectivity of the target alkanes under the optimal process parameters. The results of this study provide effective catalyst parameters for research in the field of clean energy. [ABSTRACT FROM AUTHOR]