Using the colloidal solution combustion approach, a three-dimensional mesoporous 5%Ni-CeO₂-M catalyst was developed, with Ni incorporated into the pores, and applied in the dry reforming of methane. Comprehensive characterization revealed that the 5%Ni-CeO₂-M catalyst had a large specific surface area and a three-dimensional mesoporous structure. A rich Ni-CeO₂ interface was formed by closely spaced tiny CeO₂ and NiO nanoparticles within the spherical pore wall. With very little carbon deposition over a 100 h period at 700 °C, the catalyst showed excellent activity and stability. The tiny Ni nanoparticles, along with the substantial Ni-CeO₂ interfaces that make up this three-dimensional in-form mesoporous catalyst, are responsible for the outstanding effectiveness of this 5%Ni-CeO₂-M catalyst.

It is a challenging task for selective hydrogenation of cinnamaldehyde (CAL) to hydrocinnamaldehyde (HCAL) without additional by-product formation. In this work, a La₂O₃ supported high Ni content nanoparticle catalyst was prepared for CAL selective hydrogenation. Meanwhile, Co-La₂O₃ catalysts were used as a reference catalyst. XRD, TEM, STEM-HAADF, XPS, and H₂-TPR measurements were used to investigate the physicochemical properties of Ni-La₂O₃ catalysts. The experimental results confirmed that the CAL conversion and HCAL selectivity were effectively promoted with the increase of Ni loading amounts. At a Ni/La molar ratio of four, a high HCAL selectivity of 87.4% was obtained at a CAL conversion of 88.1% under mild reaction conditions. The catalyst was recycled five times without activity loss. Combined with various characterizations, it could be inferred that the good hydrogen adsorption and dissociation capacity of Ni and the presence of a certain amount of oxygen vacancies on the La₂O₃ support have a positive effect on the improvement of HCAL selectivity. This work provided an effective path to design transition-metal-based supported oxide catalyst for the cinnamaldehyde hydrogenation to hydrocinnamaldehyde.

Highly dispersed CuO/SiO₂ catalysts were successfully synthesized by a green process of ball milling (BM) under solvent-free and room temperature conditions. The structural evolution of CuO/SiO₂ catalysts prepared by BM was elucidated by TG-DSC, XRD, FT-IR, and XPS characterizations. We found that the copper acetate precursor was dispersed over the layer of copper phyllosilicate which was formed by reacting between the copper acetate precursor and the silica support during the BM process. The copper phyllosilicate layer over the support might play an important role in the stabilization of the CuO cluster (<2 nm) during thermal pretreatment. The 15% CuO/SiO₂ catalyst exhibited the best catalytic activity for the catalytic combustion of ethyl acetate as it owned a highest active surface area of CuO among the CuO/SiO₂ catalysts with different copper loadings.

At present, the selective hydrogenation of α, β-unsaturated aldehydes remains a challenge due to competition between unsaturated functional groups (C=C and C=O). In this study, N-doped carbon deposited on silica-supported nickel Mott–Schottky type catalysts (Ni/SiO₂@N_xC) was prepared for the selective hydrogenation of cinnamaldehyde (CAL) by using the respective hydrothermal method and high-temperature carbonization method. The prepared optimal Ni/SiO₂@N₇C catalyst achieved 98.9% conversion and 83.1% selectivity for 3-phenylpropionaldehyde (HCAL) in the selective hydrogenation reaction of CAL. By constructing the Mott–Schottky effect, the electron transfer from metallic Ni to N-doped carbon at their contact interface was promoted, and the electron transfer was demonstrated by XPS and UPS. Experimental results indicated that by modulating the electron density of metallic Ni, the catalytic hydrogenation of C=C bonds was preferentially performed to obtain higher HCAL selectivity. Meanwhile, this work also provides an effective way to design electronically adjustable type catalysts for more selective hydrogenation reactions.

A series of Ce_1−XSn_XO₂ (X = 0, 0.2, 0.3, 0.4, 0.5, 0.9, 1) catalysts were synthesized via the combustion method. The physical and chemical structures of the prepared catalysts were systematically characterized by XRD, BET, SEM, TEM, XPS, and TPR. The Ce_1−XSn_XO₂ catalysts have higher catalytic activities than the mono-oxide catalysts, as there are synergistic effects between CeO₂ and SnO₂. The catalytic activities of the Ce_1−XSn_XO₂ catalysts are dependent on the X for the catalytic combustion of ethyl acetate (EA). The Ce_1−XSn_XO₂ (X < 0.5) catalysts show high catalytic performances. Meanwhile, the Ce₀.₈Sn₀.₂O₂ and Ce₀.₇Sn₀.₃O₂ catalysts display the highest catalytic performance, with T₅₀ = 190 °C and T₉₀ = 210 °C. More importantly, the Ce₀.₈Sn₀.₂O₂ catalyst exhibits superior thermal and catalytic activity stability. It is found that the Ce_1−XSn_XO₂ catalysts form solid solutions, as the X is <0.5. The reduction of Sn⁴⁺ species to Sn²⁺ is significantly promoted by the CeO₂, which is an important factor attributed to the high catalytic activities of the solid solution Ce_1−XSn_XO₂ catalysts. The catalytic activities of the Ce_1−XSn_XO₂ catalysts exhibit a strong correlation to the surface atomic areas of Ce³⁺ and O_α (V_O). In other words, the higher surface atomic areas of Ce³⁺ and O_α (V_O) are, the higher the catalytic activities will have.