Activity of CoMo/MSA Catalysts in Benzothiophene Hydrodesulfurization, Cumene Cracking and Cyclohexene is Omerization

AbstractThe mesoporous silica-alumina (SA) was modified by acid leaching and studied as an alternative support for Mo and CoMo catalysts for hydrodesulfurization (HDS) of benzothiophene. The supports were characterized by N 2 adsorption, XRD, 27AL MAS NMR, electron microscopy (SEM, HRTEM) and their acidity were compared in cyclohexene isomerization and cumene cracking. The composition of catalysts were determined by ICP. Progressive leaching of the parent SA containing 52wt.% Al2O3 (SA52) led to decrease of Al2O3 content (33 and 19wt.% in MSA33 and MSA19 support, respectively). This decrease was accompanied with an increase of the BET surface area and exposition of strong acidity. The acid leaching positively affected the activities of the sulfided CoMo catalysts in the benzothiophene HDS, which were slightly above the activity of an industrial reference CoMo catalyst supported on gamma-Al2O3

Carbon dots enabling parts-per-billion sensitive and ultraselective photoluminescence lifetime-based sensingof inorganic mercury

One of the UN Sustainable Development Goals is to ensure universal access to clean drinking water. Among the various types of water contaminants, mercury (Hg) is considered to be one of the most dangerous ones. It is mostly its immense toxicity and vast environmental impact that stand out. To tackle the issue of monitoring water quality, a nanosensor based on carbon dots (CDs) is developed, whose surface is functionalized with carboxylic groups. CDs show Hg2+ concentration-dependent photoluminescence (PL) lifetimes along with an ultrahigh sensitivity and selectivity. The selectivity of PL quenching by Hg2+ is rationalized by performing light-induced electron paramagnetic resonance (LEPR) spectroscopy showing significant perturbation of the CD photoexcited state upon Hg2+ binding. The experimental findings are supported by time-dependent density functional theory (TD-DFT) calculations. These unveiled the emergence of a low-lying charge transfer state involving a vacant 6s orbital of Hg2+ stabilized by relativistic effects.Web of Science112