Performance of a Ni-Cu-Co/Al2O3 Catalyst on in-situ Hydrodeoxygenation of Bio-derived Phenol

Hydrogen Production by Ethanol Reforming on Supported Ni-Cu Catalysts

Supported bimetallic Ni-Cu catalysts with different Ni-Cu loadings on alumina (Al₂O₃), alumina-silica (Al₂O₃-SiO₂), alumina-magnesia (Al₂O₃-MgO), alumina-zinc oxide (Al₂O₃-ZnO), and alumina-lanthanum oxide (Al₂O₃-La₂O₃) were prepared and tested in ethanol steam reforming for the production of hydrogen (H₂). These catalysts were characterized by X-ray diffraction, H₂-temperature-programmed reduction, ammonia-temperature-programmed desorption, X-ray photoelectron spectroscopy, thermogravimetry, and differential scanning calorimetry. Cu addition improved the reducibility of NiO. Among the as-prepared catalysts, 30Ni5Cu/Al₂O₃-MgO and 30Ni5Cu/Al₂O₃-ZnO demonstrated much higher H₂ selectivity and excellent coke resistance compared to the other investigated catalysts. Over 30Ni5Cu/Al₂O₃-MgO and 30Ni5Cu/Al₂O₃-ZnO, the respective H₂ selectivity was 73.3 and 63.6% at 450 °C and increased to 94.0 and 95.2% at 600 °C. The strong interaction of Ni-Cu and Al₂O₃-ZnO (or Al₂O₃-MgO) led to the formation of smaller and highly dispersed CuO and NiO species on the carrier, which is conducive to improved catalytic performance. These Al₂O₃-MgO- and Al₂O₃-ZnO-supported bimetallic Ni-Cu materials can be promising catalysts for hydrogen production from ethanol steam reforming.

Effect of Water and Glycerol in Deoxygenation of Coconut Oil over Bimetallic NiCo/SAPO-11 Nanocatalyst under N2 Atmosphere

The catalytic deoxygenation of coconut oil was performed in a continuous-flow reactor over bimetallic NiCo/silicoaluminophosphate-11 (SAPO-11) nanocatalysts for hydrocarbon fuel production. The conversion and product distribution were investigated over NiCo/SAPO-11 with different applied co-reactants, i.e., water (H₂O) or glycerol solution, performed under nitrogen (N₂) atmosphere. The hydrogen-containing co-reactants were proposed here as in-situ hydrogen sources for the deoxygenation, while the reaction tests under hydrogen (H₂) atmosphere were also applied as a reference set of experiments. The results showed that applying co-reactants to the reaction enhanced the oil conversion as the following order: N₂ (no co-reactant) < N₂ (H₂O) < N₂ (aqueous glycerol) < H₂ (reference). The main products formed under the existence of H₂O or glycerol solution were free fatty acids (FFAs) and their corresponding C_n−1 alkanes. The addition of H₂O aids the triglyceride breakdown into FFAs, whereas the glycerol acts as hydrogen donor which is favourable to initiate hydrogenolysis of triglycerides, causing higher amount of FFAs than the former case. Consequently, those FFAs can be deoxygenated via decarbonylation/decarboxylation to their corresponding C_n−1 alkanes, showing the promising capability of the NiCo/SAPO-11 to produce hydrocarbon fuels even in the absence of external H₂ source.

Editorial Catalysts: Special Issue on “Biomass Derived Heterogeneous and Homogeneous Catalysts”

The replacement of petrol products for environmentally-friendly ones is a reality today, as many governments and international organizations are promoting the implementation of renewable energy sources and natural feedstocks in industrial activity [...]

Supported Bimetallic Catalysts for the Solvent-Free Hydrogenation of Levulinic Acid to γ-Valerolactone: Effect of Metal Combination (Ni-Cu, Ni-Co, Cu-Co)

γ-valerolactone (GVL) is an important value-added chemical with potential applications as a fuel additive, a precursor for valuable chemicals, and polymer synthesis. Herein, different monometallic and bimetallic catalysts supported on γ-Al2O3 nanofibers (Ni, Cu, Co, Ni-Cu, Ni-Co, Cu-Co) were prepared by the incipient wetness impregnation method and employed in the solvent-free hydrogenation of levulinic acid (LA) to GVL. The influence of metal loading, metal combination, and ratio on the activity and selectivity of the catalysts was investigated. XRD, SEM-EDS, TEM, H2-TPR, XPS, NH3-TPD, and N2 adsorption were used to examine the structure and properties of the catalysts. In this study, GVL synthesis involves the single-step dehydration of LA to an intermediate, followed by hydrogenation of the intermediate to GVL. Ni-based catalysts were found to be highly active for the reaction. [2:1] Ni-Cu/Al2O3 catalyst showed 100.0% conversion of LA with >99.0% selectivity to GVL, whereas [2:1] Ni-Co/Al2O3 yielded 100.0% conversion of LA with 83.0% selectivity to GVL. Moreover, reaction parameters such as temperature, H2 pressure, time, and catalyst loading were optimized to obtain the maximum GVL yield. The solvent-free hydrogenation process described in this study propels the future industrial production of GVL from LA.