Multicomponent oxides are intriguing materials in heterogeneous catalysis, and the interface between various components often plays an essential role in oxidations. However, the underlying principles of how the hetero-interface affects the catalytic process remain largely unexplored. Here we report a unique structure design of MnCoO_x catalysts by chemical reduction, specifically for ethane oxidation. Part of the Mn ions incorporates with Co oxides to form spinel Mn_xCo_3-xO₄, while the rests stay as MnO₂ domains to create the MnO₂-Mn_xCo_3-xO₄ interface. MnCoO_x with Mn/Co ratio of 0.5 exhibits an excellent activity and stability up to 1000 h under humid conditions. The synergistic effects between MnO₂ and Mn_xCo_3-xO₄ are elucidated, in which the C₂H₆ tends to be adsorbed on the interfacial Co sites and subsequently break the C-H bonds on the reactive lattice O of MnO₂ layer. Findings from this study provide valuable insights for the rational design of efficient catalysts for alkane combustion.

Interface engineering is crucial in the design of supported metal catalysts, as it significantly influences the catalytic process, particularly in terms of selectivity. Herein, we discover the redispersion of Ni nanoparticles from SiO₂ to molybdenum carbide (Mo₂C) being induced by the strong interaction between metal and Mo₂C. Parameters affect such migration are thoroughly investigated from carbon source, proximity between Ni and Mo₂C to activation atmosphere and temperature. The established dual interface on Mo₂C-Ni/SiO₂ catalyst exhibits excellent catalytic performance for CO₂ hydrogenation, readily shifting the selectivity from 91% CO on Ni/Mo₂C to near 100% CH₄ on Mo₂C-Ni/SiO₂. Density functional theory calculations further verify the interfacial synergy between Ni/Mo₂C and Ni/SiO₂ sites with low barrier for CO₂ activation and a subsequent successive hydrogenation of CO. These findings highlight the important role of strong metal-support interaction (SMSI) induced metal redispersion for the rational fabrication of dual interfaces, leading to a highly active catalyst for target products.

A series of NiMo catalysts with a low MoO₃/NiO mass ratio were prepared by introducing SiO₂ and Ni during the formation of the support. The supports were improved by adding SiO₂ to optimise the surface acidity properties, regulate the main structure of the NiMoS active phase, reduce the formation proportion of NiAl₂O₄, and improve the utilisation rate of Ni. The catalysts were improved by increasing the Ni content to adjust the Ni/Mo atomic ratio at the edge and corner positions of the NiMoS active phase to promote the generation and transfer of activated hydrogen. The NiMoS phase with high Ni content achieved good dispersion on the catalyst surface, reaching the highest hydrogenation saturation depth of aromatic hydrocarbon when the MoO₃/NiO mass ratio is 3 and the SiO₂ content is 5 wt.%. The catalysts with high Ni content also exhibit high activity and stability in removing Conradson Carbon Residue (CCR) during hydrotreating. Increasing the Ni content of the catalyst helps to remove impurities such as S and N from the residual oil.

FDO’s wide boiling range and complex composition hinder controlled synthesis of high-performance mesophase pitch. Here, FDO was separated into light, middle, and heavy narrow fractions by vacuum distillation. Multi-scale characterization traced molecular evolution and mesophase development. The light fraction consists of three-ring aromatics with short alkyl side chains and shows the lowest reactivity, yielding limited condensation and poor stacking with isotropic regions and dispersed spheres. The middle fraction contains four-ring aromatics with moderately extended chains, exhibiting enhanced reactivity and undergoing nucleation, growth, coalescence, and disintegration of mesophase spheres. However, insufficient volatiles restrict shear orientation, forming a mosaic texture. The heavy fraction has four-ring aromatics with the longest alkyl chains and the lowest substitution degree, giving the highest reactivity. During thermal cracking, long chains release abundant radicals and volatiles; directional escape generates shear, promoting rapid growth and ordered alignment of aromatic lamellae. At 440 °C for 12 h, this fraction yields high-quality mesophase pitch with small-domain texture, a low softening point (295 °C), and high anisotropic content (98.8%). The pitch shows excellent spinnability, and derived carbon fibers (tensile strength ~1.45 GPa, modulus ~151 GPa) outperform a commercial reference processed under identical conditions. This study reveals molecular-level regulation of mesophase evolution by narrow fraction structures.