Co@CoO: a Unique Catalyst for Hydrogenolysis of Biomass-derived 5-Hydroxymethylfurfural to 2,5-Dimethylfuran

The development of precious-metal-free catalysts to promote the sustainable production of fuels and chemicals from biomass remains an important and challenging target. Here, we report the efficient hydrogenolysis of biomass-derived 5-hydroxymethylfurfural to 2,5-dimethylfuran over a unique core-shell structured catalyst Co@CoO that affords the highest productivity among all catalysts reported to date. Surprisingly, we found that the catalytically active sites reside on the shell of CoO with oxygen vacancies rather than the metallic Co. The combination of various spectroscopic experiments and computational modelling reveals that the CoO shell incorporating oxygen vacancies drives the heterolytic and homolytic cleavage of dihydrogen to yield active Hδ- species, resulting in the exceptional catalytic activity. Co@CoO also exhibits excellent activity toward the direct hydrodeoxygenation of lignin model compounds. This study unlocks, for the first time, the potential of metal-oxide catalysts for the production of renewable biomass-derived fuels.

THE KINETICS AND MECHANISM OF THE SELECTIVE OXIDATIVE DEHYDROGENATION REACTİON OF METHYLCYCLOPENTANE

The oxidative dehydrogenation of alicyclic diene hydrocarbons refers to scarcely studied heterogeneous catalytic reactions which proceed with the participation of oxygen. The dehydrogenation of methylcyclopentane is an endothermic reaction. To improve the reaction kinetics, this research was to develop a structured catalyst by conductive metals (Cu, Zn, Co, Cr) support which could hold an adherent catalytic layer. The active phase was impregnated onto these support metals and the developed catalyst was tested for the dehydrogenation of methylcyclopentane. The catalyst preparation involved three main key steps which were support oxidative reaction, loading of active particles on the catalyst surface, preparation of an active catalyst layer on the surface finally bringing the catalyst into the active phase. Different types of catalyst activation and deactivation mechanisms stability have been studied in this investigation. The advantage of this works, the oxidative dehydrogenation of methylcyclopentane is that it occurs at the expense of oxygen in the air. The zeolite structure study helped identify the effect of the combination of catalysts, and adsorption of metals on clinoptilolite and dispersion on the selectivity of the catalyst particles. Numerical values of the kinetic parameters were calculated

Synthesis of Catalytic Ni/Cu Nanoparticles from Simulated Wastewater on Li–Al Mixed Metal Oxides for a Two-Stage Catalytic Process in Ethanol Steam Reforming: Catalytic Performance and Coke Properties

This work recovered Ni or Cu cations from simulated electroplating wastewater to synthesize Ni/Cu nano-catalysts for H2 generation by ethanol steam reforming (ESR). Aluminum lathe waste was used as a framework to prepare the structured catalyst. Li–Al–CO3 layered double hydroxide (LDH) was electrodeposited on the surface of the framework. The LDH was in a platelet-like structure, working as a support for the formation of the precursor of the metal catalysts. The catalytic performance and the coke properties of a 6Cu_6Ni two-stage catalyst configuration herein used for ESR catalytic reaction were studied. The Cu–Ni two-stage catalyst configuration (6Cu_6Ni) yielded more H2 (~10%) than that by using the Ni-based catalyst (6Ni) only. The 6Cu_6Ni catalyst configuration also resulted in a relatively stable H2 generation rate vs. time, with nearly no decline during the 5-h reaction. Through the pre-reaction of ethanol-steam mixture with Cu/LiAlO2 catalyst, the Ni/LiAlO2 catalyst in the 6Cu_6Ni catalyst configuration could steadily decompose acetaldehyde, and rare acetate groups, which would evolve condensed coke, were formed. The Ni nanoparticles were observed to be lifted and separated by the carbon filaments from the support and had no indication of sintering, contributing to the bare deactivation of the Ni/LiAlO2 catalyst in 6Cu_6Ni.

Cellulose Beads as Novel Support of Copper Active Site for the Catalytic Abatement of Water Emerging Contaminant

Different regenerated cellulose (RC) beads were synthesized as supports of copper as the active site for catalytic degradation of emerging contaminants (ECs) in water. Starting from a commercial dissolving pulp, RC beads were prepared from the direct dissolution and from both cellulose carbamate and viscose solutions. Copper was added to the supports by a simple green method. The material characterization by FTIR, TGA, SEM and XPS confirmed the successful incorporation of copper in all the prepared supports. Phenol was adopted as EC test molecule, and catalytic wet peroxide oxidation (CWPO) at 70°C was used to analyse the Cu-cellulosic beads catalytic performance. The novelty and importance of preparing bead-shape catalysts with cellulose reside in the use of an economic, renewable and biodegradable matrix, and the simple separation of the structured catalyst from the heterogeneous solid/liquid reaction media.