Activated carbon-supported HgCl₂ catalysts have seriously impeded the development of the polyvinyl chloride (PVC) industry due to the sublimation of Hg species and environmental pollution problems. Herein, the template-free and organic solvent-free strategy was devised to synthesize non-metallic based nitrogen-doped carbon (U-NC) sphere catalyst for acetylene hydrochlorination. This green strategy via ultrasonic chemistry initiates resin crosslinking reactions between aminophenol and formaldehyde resin by free radicals, leading to the ultra-rapid formation of U-NC with remarkably high pyrrolic N content in only 5 min. This U-NC catalyst exhibited an outstanding space-time-yield (1.6 g_VCM·g_cat⁻¹·h⁻¹), even comparable to the reported metallic catalyst. By combining kinetic analysis, advanced characterizations, and density functional theory, it is found that the amount of pyrrolic N is in linear with C₂H₂ conversion, and pyrrolic N in U-NC can effectively improve acetylene hydrochlorination performance by mediating HCl adsorption. This work sheds new light on rationally constructing metal-free catalyst for acetylene hydrochlorination.

Upgrading of vacuum residue is of prime industrial significance due to the increasing demand for light oils. Elucidating the effect of catalyst morphology on vacuum residue hydrotreating performance by kinetic modeling is therefore of great importance. Herein, kinetic analysis of hydrodemetallization (HDM) and hydrodeconradson-carbon-residue (HDCCR) performances on industrial Ni–Mo/Al₂O₃ catalysts with spherical and cylindrical morphologies in ebullated-bed were evaluated for more than 1600 h. It was found that the percentage of light impurities easier to be removed on spherical catalysts were 78.20% and 39.43% in HDM and HDCCR reactions, respectively, higher than 65.20% and 17.50% on cylindrical catalysts. This suggests that catalyst morphology affects the impurity removal ability and the impurity properties, resulting in better hydrotreating performance of spherical catalysts. This work not only combines catalyst morphology with impurity removal capability through kinetic modeling, but also provides new insights into the design of efficient hydrotreating catalysts.