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Furfural (FFR) was selectively hydrogenated in a single pot to tetrahydrofurfuryl alcohol (THFAL) over a Si–MFI molecular sieve supported Pd catalyst. Studies on catalyst screening revealed that both the metal function and the support were critical for directing the selectivity to the ring-hydrogenated product, THFAL. The structural feature of MFI as shown by XRD was completely retained in the used sample of the 3% Pd/MFI catalyst confirming its stability under reaction conditions. XRD, along with SEM characterization of the used samples, established retention of morphology of the structured silicate, suggesting a strong interaction between hexagonal porous silicate and Pd particles. The complete conversion of FFR with an enhanced selectivity of 95% to THFAL could be achieved by recycling the crude of the first hydrogenation experiment over the same 3% Pd/MFI catalyst.

Non-chromium Cu:Al nano catalyst prepared by simultaneous co-precipitation and digestion method without any template or stabilizer, showed three times higher activity than the bulk Cu-Cr catalyst for hydrogenolysis of glycerol in both isopropanol and water solvents, with the selectivity to 1,2-Propanediol (1,2-PDO) as high as 91% at 493 K and H 2 pressure of 7 MPa in 5 h. XRD pattern showed the presence of Cu ? species in the activated Cu:Al nano catalyst. Although Cu ? is catalytically inactive in glycerol hydrogenolysis reaction, the presence of Cu ? helps to stabilize the particle size in a narrow range of 7-11 nm by inhibiting the sintering of copper particles under reaction conditions.

Ni and NiSn supported on zirconia (ZrO 2 ) and on indium (In)-incorporated zirconia (InZrO 2 ) catalysts were prepared by a wet chemical reduction route and tested for hydrogenation of CO 2 to methanol in a fixed-bed isothermal flow reactor at 250 °C. The mono-metallic Ni (5%Ni/ZrO 2 ) catalysts showed a very high selectivity for methane (99%) during CO 2 hydrogenation. Introduction of Sn to this material with the following formulation 5Ni5Sn/ZrO 2 (5% Ni-5% Sn/ZrO 2 ) showed the rate of methanol formation to be 0.0417 μmol/(g cat ·s) with 54% selectivity. Furthermore, the combination NiSn supported on InZrO 2 (5Ni5Sn/10InZrO 2 ) exhibited a rate of methanol formation 10 times higher than that on 5Ni/ZrO 2 (0.1043 μmol/(g cat ·s)) with 99% selectivity for methanol. All of these catalysts were characterized by X-ray diffraction, high-resolution transmission electron microscopy (HRTEM), scanning transmission electron microscopy (STEM), X-ray photoelectron spectroscopy, CO 2 -temperature-programmed desorption, and density functional theory (DFT) studies. Addition of Sn to Ni catalysts resulted in the formation of a NiSn alloy. The NiSn alloy particle size was kept in the range of 10–15 nm, which was evidenced by HRTEM study. DFT analysis was carried out to identify the surface composition as well as the structural location of each element on the surface in three compositions investigated, namely, Ni 28 Sn 27 , Ni 18 Sn 37 , and Ni 37 Sn 18 bimetallic nanoclusters, and results were in agreement with the STEM and electron energy-loss spectroscopy results. Also, the introduction of “Sn” and “In” helped improve the reducibility of Ni oxide and the basic strength of catalysts. Considerable details of the catalytic and structural properties of the Ni, NiSn, and NiSnIn catalyst systems were elucidated. These observations were decisive for achieving a highly efficient formation rate of methanol via CO 2 by the H 2 reduction process with high methanol selectivity.

Various noble metal catalysts were screened in a batch operation for a furfural (FFR) single-step decarbonylation and hydrogenation reaction to obtain THF in high selectivity. Among these, the 3% Pd/C showed complete FFR conversion with a total of 80% selectivity to ring hydrogenated products including tetrahydrofuran (THF). The order of activity exhibited by other noble metals was Pt/C > Re/C > Ru/C. Although Pt/C exhibited the highest activity, its decarbonylation and ring hydrogenation ability were the least (24%) with a major product selectivity of 66% to furfuryl alcohol (FAL). Similarly, the Cu catalyst gave almost complete selectivity to FAL. In a continuous operation (23 g catalyst bed), the 3% Pd/C catalyst showed higher selectivity of >40% compared to THF alone with complete FFR conversion and on-stream activity of ∼100 h. The reaction pathway elucidated from some control experiments revealed that the decarbonylation of FFR to furan over the Pd/C catalyst is a prerequisite for THF formation.

Various iridium supported carbon catalysts were prepared and screened for the direct hydrogenation of furfural (FFR) to 2-methyl furan (2-MF).

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