CeO₂, ZrO₂, and CeO₂–ZrO₂ supported on MgO-promoted Ni catalysts are developed and applied to the reforming of methane with carbon dioxide. The catalysts are prepared by the one-step co-precipitation/aging method and characterized through various techniques such as X-ray diffraction, Brunauer–Emmet–Teller measurements, pore distribution, X-ray photoelectron spectroscopy, X-ray absorption near edge spectroscopy, extended X-ray absorption fine structure analysis, H₂-temperature programmed reduction, H₂-chemisorption, Raman analysis, thermogravimetry analysis, and pulse H₂–CO₂ reactions. Ni–MgO–CeO₂ shows the smallest Ni particle size and the particle size decreases with increasing ZrO₂ content. Ni–MgO–Ce_0.6Zr_0.4O₂ exhibits the largest oxygen storage capacity among the prepared catalysts. The size of the Ni particles and the oxygen storage capacity are found to be the primary and secondary key factors that influence the catalytic performance, respectively. The turnover frequency is dependent on the size of the Ni particles, but the catalytic performance is affected by the number of Ni active sites, which is estimated from the reduction degree and Ni particle size. Overall, the Ni–MgO–Ce_0.8Zr_0.2O₂ catalyst shows the best performance owing to the high reduction degree and small Ni particle size.

The development of an efficient non-sulfided and non-precious catalyst for selective hydrogenation (HD) and hydrodeoxygenation (HDO) of biomass-derived feedstocks to produce fuels and chemicals is of great interest. In this study, a highly efficient bimetallic Ga-doped Cu/H-nanozeolite-Y (Cu/HNZY) catalyst was developed for selective HD and HDO of lignin-derived species (vanillin, acetovanillone, and cinnamaldehyde) under mild conditions (120–180 °C, 1 MPa H₂). The HNZY support exhibited a mesoporous structure with a large external surface area, which can facilitate reactant adsorption. Ga doping not only increased the Cu dispersion and Lewis acidity, but produced low coordinated Ga species (e.g., Ga⁺ and (GaH₂)⁺), which could enhance the HDO activity. As a result, at 160 °C for 2 to 5 h, complete conversion of vanillin and acetovanillone into their decarbonylated species (creosol and 4-ethylguiuacol) with high selectivity (>99%) could be achieved at a low H₂ initial pressure of 1 MPa. In addition, when cinnamaldehyde was converted over Ga-doped Cu/HNZY at 180 °C, selective HD and HDO followed by cyclization formed high amounts of indane and its derivatives, which have a variety of applications in pharmaceutical and agricultural industries. This could open a new possibility for lignin-to-drug intermediates.

For a solid acid-catalyzed dehydration of biomass-derived carbohydrates into useful furan derivatives, a suitable porous solid acid catalyst having an optimum acidic density and its strength is required to avoid cascade reactions in biomass conversion processes. A large-pore mesoporous zirconium phosphate (m-ZrP) was prepared hydrothermally using P123 as a template in water solvent, which resulted in a higher pore diameter (>9 nm) having wormhole-like pore structures with balanced Lewis (L) to Brönsted (B) acid sites. The effects of calcination temperature (500–800 °C) on the textural, acidic/basic, and structural properties of the m-ZrP with its catalytic performance for glucose dehydration to 5-hydroxymethylfurfural (HMF) were investigated in a pure water media as a green and sustainable alternative solvent. The larger number of L and B acid sites and basic sites with their appropriate strengths were clearly related with a better catalytic performance in terms of glucose conversion and HMF yield. The strong L acid and basic sites in the m-ZrP efficiently promoted the glucose isomerization to fructose, which dehydrated exclusively on the weak B acid sites resulting in a maximum conversion of glucose (83.8%) and HMF yield (46.6%). The adjusted acidic and basic sites with large mesopore sizes make the m-ZrP yield a higher reaction rate (2.78 mmol g_cat^–1 h^–1) and turnover frequency (11.68/h) for conversion of glucose to HMF, which showed higher catalytic activity than those of a small-pore m-ZrP and other mesoporous heterogeneous and homogeneous acid catalysts.