Copper phyllosilicate-derived ultrafine copper nanoparticles with plenty of Cu0and Cu+ for the enhanced catalytic performance of ethylene carbonate hydrogenation to methanol

The hydrogenation of CO₂-derived carbonates to methanol is an alternative route for the indirect utilization of abundant C1 sources. Various Cu/SiO₂catalysts with different copper loading content prepared by using an ammonia evaporation hydrothermal method are implemented to evaluate the catalytic performance of ethylene carbonate (EC) hydrogenation to methanol and ethylene glycol (EG). The Cu loading content was identified to significantly affect the Cu nanoparticles (NPs) size and metal-support interaction. Highly dispersed Cu NPs restricted and embedded in copper phyllosilicate presented a smaller average particle size than the impregnated Cu/SiO₂-IM catalyst. ThexCu/SiO₂catalyst with ultrafine Cu NPs showed abundant Cu-O-Si interfaces, acidic sites, and coherent Cu⁰and Cu⁺species. The 5Cu/SiO₂catalyst achieved methanol yield of 76% and EG yield of 98% at EC conversion of 99%, and no obvious deactivation was observed after long-term operation. The superior catalytic performance of the 5Cu/SiO₂catalyst is attributed to the synergetic effect between the appropriate Cu⁰surface area which provides sufficient active hydrogen, and the atomic ratio of Cu⁺for the polarization and activation of carbon-oxygen bonds.

Selective hydrogenolysis of 5-hydroxymethylfurfural to 2,5-dimethylfuran over cobalt nanoparticle inlaid cobalt phyllosilicate

Fabrication of biofuels and chemicals from renewable biomass is highly desirable to replace petrochemicals. Hydrogenolysis of biomass derived 5-hydroxymethylfurfural (HMF) is a promising way to obtain furanic fuels. In this paper, we describe the preparation of a CoSi-PS catalyst derived from cobalt phyllosilicate using a silica sol as the silica source. CoSi-PS exhibited excellent catalytic performance for the hydrogenolysis reaction of HMF to produce liquid 2,5-dimethylfuran (DMF) biofuel. 100% conversion of HMF and 97.5% selectivity for DMF were achieved at 170 °C and 1.5 MPa H₂ for 4 h, which was superior to most of the reported catalysts. The excellent performance can be attributed to the strong interactions between the metal and support, highly dispersed cobalt nanoparticles and the Lewis acid sites induced by the coordinated unsaturated Co(II) sites in phyllosilicate.

Regulation of Brønsted acid sites to enhance the decarburization of hexoses to furfural

H-Beta zeolites were employed for hexose decarburization to furfural. Excellent performance was achieved over high-Si H-Beta zeolite due to its high B/(B + L) ratio. The synergetic mechanism between *BEA channel and framework-Al is decisive.

Earth-abundant 3d-transition-metal catalysts for lignocellulosic biomass conversion

Transformation of biomass to chemicals and fuels is a long-term goal in both science and industry. However, high cost is one of the major obstacles to the industrialization of this sustainable technology. Thus, developing catalysts with high activity and low-cost is of great importance for biomass conversion. The last two decades have witnessed the increasing achievement of the use of earth-abundant 3d-transition-metals in catalysis due to their low-cost, high efficiency and excellent stability. Here, we aim to review the fast development and recent advances of 3d-metal-based catalysts including Cu, Fe, Co, Ni and Mn in lignocellulosic biomass conversion. Moreover, present research trends and invigorating perspectives on future development are given.

Copper Phyllosilicates-Derived Catalysts in the Production of Alcohols from Hydrogenation of Carboxylates, Carboxylic Acids, Carbonates, Formyls, and CO2: A Review

Copper phyllosilicates-derived catalysts (CuPS-cats) have been intensively explored in the past two decades due to their promising activity in carbonyls hydrogenation. However, CuPS-cats have not been completely reviewed. This paper focuses on the aspects concerning CuPS-cats from synthesis methods, effects of preparation conditions, and dopant to catalytic applications of CuPS-cats. The applications of CuPS-cats include the hydrogenation of carboxylates, carboxylic acids, carbonates, formyls, and CO2 to their respective alcohols. Besides, important factors such as the Cu dispersion, Cu+ and Cu0 surface areas, particles size, interaction between Cu and supports and dopants, morphologies, and spatial effect on catalytic performance of CuPS-cats are discussed. The deactivation and remedial actions to improve the stability of CuPS-cats are summarized. It ends up with the challenges and prospective by using this type of catalyst.

Modification of composite catalytic material CumVnOx@CeO2 core-shell nanorods with tungsten for NH3-SCR

Novel composite material CumVnOx-NF@Ce-MOF nanorods with a core-shell structure were successfully fabricated by the in situ growth of Ce-MOF on electrospun copper vanadate precursor nanofibers. Following calcination at 500, 600 and 700 °C, Cu2V2O7@CeO2, Cu3(VO4)2@CeO2 and Cu11O2(VO4)6@CeO2, respectively, were obtained. The CeO2 shell not only protected the copper vanadate nanofibers from breaking apart during the calcination process, but also induced an interaction between Ce, Cu and V species, which resulted in an excellent redox capacity. This revealed its potential as a catalyst for the selective catalytic reduction of nitrogen oxides with NH3 (NH3-SCR). Further surface modulation was accomplished by WOx anchoring on the shell of CumVnOx@CeO2. According to a series of characterizations, the crystallinity of surface ceria on CumVnOy@CeO2-WOx was apparently reduced and the amount of acid on its surface was also significantly increased. In addition, different calcination temperatures also had nonnegligible effects on the amount of surface acid as well as the redox capacity of the composite catalytic material CumVnOy@CeO2-WOx. With the largest total quantity of acid sites as well as a suitable balance between acidity and reducing ability, the Cu3(VO4)2@CeO2-WOx calcined at 600 °C exhibited satisfactory catalytic performance in the NH3-SCR process, and the NO conversion could remain above 90% at 230-380 °C.

Recent Advances in Catalytic Hydrogenation of Furfural

Furfural has been considered as one of the most promising platform molecules directly derived from biomass. The hydrogenation of furfural is one of the most versatile reactions to upgrade furanic components to biofuels. For instance, it can lead to plenty of downstream products, such as (tetrahydro)furfuryl alcohol, 2-methyl(tetrahydro)furan, lactones, levulinates, cyclopentanone(l), or diols, etc. The aim of this review is to discuss recent advances in the catalytic hydrogenation of furfural towards (tetrahydro)furfuryl alcohol and 2-methyl(tetrahydro)furan in terms of different non-noble metal and noble metal catalytic systems. Reaction mechanisms that are related to the different catalytic materials and reaction conditions are properly discussed. Selective hydrogenation of furfural could be modified not only by varying the types of catalyst (nature of metal, support, and preparation method) and reaction conditions, but also by altering the reaction regime, namely from batch to continuous flow. In any case, furfural catalytic hydrogenation is an open research line, which represents an attractive option for biomass valorization towards valuable chemicals and fuels.