The selective oxidation of methane under mild conditions remains the “Holy Grail of Catalysis”. The key to activating methane and inhibiting over-oxidation of target oxygenates lies in designing active centers. Copper nanoparticles were loaded onto TiO₂ nanofibers using the photo-deposition method. The resulting catalysts were found to effectively convert methane into C1 oxygenated products under mild conditions. Compared with previously reported catalysts, it delivers a superior performance of up to 2510.7 mmol·g_Cu⁻¹·h⁻¹ productivity with a selectivity of around 100% at 80 °C for 5 min. Microstructure characterizations and density functional theory (DFT) calculations indicate that TiO₂ in the mixed phase of anatase and rutile significantly increases the Cu⁺/Cu⁰ ratio of the supported Cu species, and this ratio is linearly related to the formation rate of oxygen-containing species. The Cu_I site promotes the generation of active O species from H₂O₂ dissociation on Cu₂O (111). These active O species reduce the energy barrier for breaking the C–H bond of CH₄, thus boosting the catalytic activity. The methane conversion mechanism was proposed as a methyl radical pathway to form CH₃OH and CH₃OOH, and then the generated CH₃OH is further oxidized to HOCH₂OOH.

Yolk-shell SiO₂ particles (YP) with center-radial meso-channels were fabricated through a simple and effective method. Al-containing YP-supported NiMo catalysts with different Al amounts (NiMo/AYP-x, x = Si/Al molar proportion) were prepared and dibenzothiophene (DBT) and 4,6-dimethyl-dibenzothiophene (4,6-DMDBT) were employed as the probes to evaluate the hydrodesulfurization (HDS) catalytic performance. The as-prepared AYP-x carriers and corresponding catalysts were characterized by some advanced characterizations to obtain deeper correlations between physicochemical properties and the HDS performance. The average pore sizes of series AYP-x supports are above 6.0 nm, which favors the mass transfer of organic sulfides. The cavity between the yolk and the shell is beneficial for the enrichment of S-containing compounds and the accessibility between reactants and active metals. Aluminum embedded into the silica framework could facilitate the formation of Lewis (L) and Brønsted (B) acid sites and adjust the metal-support interaction (MSI). Among all the as-synthesized catalysts, NiMo/AYP-20 catalyst shows the highest HDS activities. The improved HDS activity of NiMo/AYP-20 catalyst is attributed to the perfect combination of excellent structural properties of the yolk-shell mesoporous silica, enhanced acidity, moderate MSI, and good accessibility/dispersion of active components.

Air pollution from particulate matter produced by incomplete combustion of diesel fuel has become a serious environmental pollution problem, which can be addressed by catalytic combustion. In this work, a series of K-modified MnO_δ catalysts with different microstructures were synthesized by the hydrothermal method, and the relationship between structure of the catalysts and their catalytic performance for soot combustion was studied by characterization techniques and density functional theory (DFT) calculations. Results showed that the prepared catalysts had good catalytic performance for soot combustion and could completely oxidize soot at temperatures below 400 °C. The cryptomelane-type K_2−xMn₈O₁₆ (K-OMS-2) with tunnel structure had excellent NO oxidation capacity and abundance of Mn⁴⁺ ions (Mn⁴⁺/Mn³⁺ = 1.24) with good redox ability, and it demonstrated better soot combustion performance than layered birnessite-type K₂Mn₄O₈ (K-OL-1). The T₁₀, T₅₀, and T₉₀ temperatures of K-OMS-2 were 269, 314, and 346 °C, respectively. The K-OMS-2 catalyst also showed excellent stability after five catalytic cycles, with T₁₀, T₅₀, and T₉₀ values holding in the ranges of 270 ± 2, 316 ± 2, and 348 ± 3 °C, respectively.