Although considerable progress has been made in direct synthesis gas (syngas) conversion to light olefins (C2(=)-C4(=)) via Fischer-Tropsch synthesis (FTS), the wide product distribution remains a challenge, with a theoretical limit of only 58% for C2-C4 hydrocarbons. We present a process that reaches C2(=)-C4(=) selectivity as high as 80% and C2-C4 94% at carbon monoxide (CO) conversion of 17%. This is enabled by a bifunctional catalyst affording two types of active sites with complementary properties. The partially reduced oxide surface (ZnCrO(x)) activates CO and H2, and C-C coupling is subsequently manipulated within the confined acidic pores of zeolites. No obvious deactivation is observed within 110 hours. Furthermore, this composite catalyst and the process may allow use of coal- and biomass-derived syngas with a low H2/CO ratio.

The key of syngas (a mixture of CO and H2) chemistry lies in controlled dissociative activation of CO and C–C coupling. We demonstrate here that a bifunctional catalyst of partially reducible manganese oxide in combination with SAPO-34 catalyzes the selective formation of light olefins, which validates the generality of the OX-ZEO (oxide-zeolite) concept for syngas conversion. Results from in situ ambient-pressure X-ray photoelectron spectroscopy, infrared spectroscopy, and temperature-programmed surface reactions reveal the critical role of oxygen vacancies on the oxide surface, where CO dissociates and is converted into surface carbonate and carbon species. They are converted to CO2 and CH x in the presence of H2. The limited C–C coupling and hydrogenation activities of MnO enable the reaction selectivity to be controlled by the confined pores of SAPO-34. Thus, a selectivity of light olefins up to 80% is achieved, far beyond the limitation of Anderson–Shultz–Flory distribution. These findings open up possibilities to explore other active metal oxides for more efficient syngas conversion.

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ARTICLE This journal isSelective hydrogenation of 5-hydroxymethylfurfural (HMF) is of great importance for future energy and chemical supply. Herein, we propose for the first time that non-noble Ni-Al 2 O 3 catalysts derived from hydrotalcite-like compounds can efficiently and selectively convert HMF to 2,5-dimethylfuran (DMF), 2,5-dimethyltetrahydrofuran (DMTHF) and 2,5dihydroxymethyltetrahydrofuran (DHMTHF). Homogeneous elemental distributions of hydrotalcite-like precursor facilitate the good dispersion of Ni and Al 2 O 3 species and strong interaction between them over the resulted catalysts. The catalysts therefore exhibited superior reactivity. Through fine modulation of surface metal-acid bifunctional sites and control of reaction conditions, high yields of DMF (91.5%), DMTHF (97.4%) and DHMTHF (96.2%) can be diversely achieved. The results demonstrate the feasibility of Ni catalysts for selective hydrogenation of C=O, C=C and C-O bonds, which have great potential for biomass utilization. ARTICLEThis journal is © The Royal Society of Chemistry 2015Green Chem., 2015, 00, 1-3 | 9 TPD) and CO temperature programmed desorption (CO-TPD) were performed on a Tianjin XQ TP-5080 instrument. Temperature programmed desorption of NH 3 (NH 3 -TPD) experiments were conducted on the AutoChem II. 2920 instrument (Micromeritics, USA) equipped with a mass spectrum detector. (See supporting information for details about the characterizations). Catalyst tests:The tests were performed over a 100 mL tank reactor. For a typical procedure, the reactor was fed with HMF (1.5 g), NiAl-CT and 1,4-dioxane (35 mL), then sealed and purged by H 2 (5 times). After that, the reactor was filled with H 2 in desired pressure and heated to objective temperature. After the test, the reactor was quenched in icewater, and then the liquid and gas products were analysed by a GC instrument with a FID detector. Notes and references

The catalytic mechanisms and catalyst design strategies for 5-hydroxymethylfural conversion are summarized.

Hydrogenolysis of carbon–oxygen bonds is a versatile synthetic method, of which hydrogenolysis of bioderived 5-hydroxymethylfurfural (HMF) to furanic fuels is especially attractive. However, low-temperature hydrogenolysis (in particular over non-noble catalysts) is challenging. Herein, nickel nanoparticles (NPs) inlaid nickel phyllosilicate (NiSi-PS) are presented for efficient hydrogenolysis of HMF to yield furanic fuels at 130–150 °C, being much superior with impregnated Ni/SiO2 catalysts prepared from the same starting materials. NiSi-PS also shows a 2-fold HMF conversion intrinsic rate and 3-fold hydrogenolysis rate compared with the impregnated Ni/SiO2. The superior performance originated from the synergy of highly dispersed nickel NPs and substantially formed acid sites due to coordinatively unsaturated Ni (II) sites located at the remnant nickel phyllosilicate structure, as revealed by detailed characterizations. The model reactions over the other reference catalysts further highlighted the metal–acid synergy for hydrogenolysis reactions. NiSi-PS can also efficiently catalyze low-temperature hydrogenolysis of bioderived furfural and 5-methylfurfural, demonstrating a great potential for other hydrogenolysis reactions.

Ethanol synthesis from syngas via dimethyl oxalate (DMO) hydrogenation is of crucial importance for environment- and energy-related applications. Herein, we designed the bifunctional Cu nanoparticle (NP) inlaid mesoporous Al2O3 catalyst and first applied it to ethanol synthesis with high efficiency. The catalyst was made based on the spatial restriction strategy by pinning the Cu NPs on mesoporous Al2O3 to conquer the sintering problem and facilitate the stability (>200 h at 270 °C), which has potential values in high-temperature and exothermic reactions. The plentiful pores, highly exposed and properly assembled Cu-acid sites, furnished the catalyst with high ethanol yield (∼94.9%). A structure-sensitive behavior that the intrinsic activity increases with the decreasing NP size was discussed. It was attributed to the change in metal–acid interfacial sites, morphology, and electronic structure and balance of surface Cu0–Cu+ species. The mechanism for DMO hydrogenation to ethanol involving activation of CO, C–O, and O–H bands was also proposed. As cleavage of these bonds is a versatile tool to utilize bioderived molecules (e.g., polyols), the bifunctional catalysts can also be applied to hydrogenolysis of C–O bonds or etherification of O–H groups to produce various chemicals.

Selective conversion of 5-hydroxymethylfurfural (HMF) can produce sustainable fuels and chemicals.Herein, Cu-ZnO catalysts derived from minerals (malachite, rosasite and aurichalcite) were employed for selective hydrogenation of HMF for the first time. High yields of 2,5-dihydroxymethylfuran (~99.1%) and 2,5-dimethylfuran (~91.8%) were obtained tunably over the catalyst with a Cu/Zn molar ratio of 2, due to the well-dispersed metal sites tailored by mineral precursors, well-controlled surface sites and optimized reaction conditions. The relationship between catalytic performance and catalyst properties was elucidated by characterization based on the composition and the structural and surface properties, and catalytic tests.The catalyst can also be extended to selective hydrogenation of other bio-derived molecules (furfural and 5-methylfurfural) to target products. The construction of mineral-derived Cu-ZnO catalysts and the revelation of the structure-performance relationship can be applied to further rational design and functionalization of non-noble Cu catalysts for selective conversion of bio-derived compounds.Catal. Sci. Technol. This journal is