Formation mechanism of active sites with enhanced DBT hydrodesulfurization performance in high-loading NiMoW/SiO2 catalysts during secondary sulfidation

Synthesis of NiMo catalysts supported on mesoporous silica FDU-12 with different morphologies and their catalytic performance of DBT HDS

Niobium modification effects on hydrodesulfurization of 4,6-DMDBT catalyzed on Ni-Mo-S active sites: A combination of experiments and theoretical study

Effects of Ni–Al2O3 interaction on NiMo/Al2O3 hydrodesulfurization catalysts

Role of the solvent evaporating temperature on the NiMo/TiO2-Al2O3 catalyst and the hydrodesulfurization performance for 4,6-dimenthyldibenzothiophehe

Scalable fabrication and active site identification of MOF shell-derived nitrogen-doped carbon hollow frameworks for oxygen reduction

The synthesis of the first completely characterized transition-metal complex containing a sulfur-bound 4,6-dimethyldibenzothiophene (4,6-Me(2)DBT) ligand, [CpRu(CO)(2)(eta(1)(S)-4,6-Me(2)DBT)]BF(4) (1) (Cp = eta(5)-C(5)Me(5)), is reported. X-ray studies of 1 and its 4-methyldibenzothiophene and dibenzothiophene analogues, [CpRu(CO)(2)(eta(1)(S)-4-MeDBT)]BF(4) (2) and [CpRu(CO)(2)(eta(1)(S)-DBT)]BF(4) (3), show that the Ru-S bond distances increase in the order, 3 < 2 < 1. Equilibrium studies on the series of [CpRu(CO)(2)(eta(1)(S)-DBTh)](+) compounds, where DBTh = DBT, 4-MeDBT, 4,6-Me(2)DBT, and 2,8-Me(2)DBT, show that the relative binding strengths of the dibenzothiophene ligands increase in the order 4,6-Me(2)DBT (1) < 4-MeDBT (20.2(1)) < DBT (62.7(6)) < 2,8-Me(2)DBT (223(3)). These results are the first to quantify the steric effect of 4- and 6-methyl groups on the sulfur-coordinating ability of dibenzothiophenes to transition-metal centers. They are also consistent with the proposal that 4- and 6-methyl groups reduce the coordination of dibenzothiophenes to active metal sites on hydrodesulfurization catalysts, which could account for the slow rate of 4-MeDBT and 4,6-Me(2)DBT hydrodesulfurization in petroleum feedstocks.

Controlling the growth of ZnNiMoSx on biomass-derived porous carbon materials for deep hydrodesulfurization

The “active sites” were identified in the ensemble of soot particles, the place of their location, the nature of their structure. The mechanism of the formation and physico-chemical properties of the pyrolytic carbon film were studied in hydrocarbon flames. Integrated technique, including infrared spectral analysis, sampling of the condensed combustion products, studying of the surface topography of the soot particles, finding values of the optical constants, revealing irregularities in the brightness of the flame, identify irregularities in the brightness of the flame can be applied in the research of mechanisms of soot formation in heterogeneous condensed media.

Preparation of highly dispersed desulfurization catalysts and their catalytic performance in hydrodesulfurization of dibenzothiophene

Support effect on the catalytic activity and properties of sulfided molybdenum catalysts

Synthesis of NiMo catalysts supported on mesoporous Al-SBA-15 with different morphologies and their catalytic performance of DBT HDS

Caspase-2, the most evolutionarily conserved member in the human caspase family, may play important roles in stress-induced apoptosis, cell cycle regulation, and tumor suppression. In biochemical assays, caspase-2 uniquely prefers a pentapeptide (such as VDVAD) rather than a tetrapeptide, as required for efficient cleavage by other caspases. We investigated the molecular basis for pentapeptide specificity using peptide analog inhibitors and substrates that vary at the P5 position. We determined the crystal structures of apo caspase-2, caspase-2 in complex with peptide inhibitors VDVAD-CHO, ADVAD-CHO, and DVAD-CHO, and a T380A mutant of caspase-2 in complex with VDVAD-CHO. Two residues, Thr-380 and Tyr-420, are identified to be critical for the P5 residue recognition; mutation of the two residues reduces the catalytic efficiency by about 4- and 40-fold, respectively. The structures also provide a series of snapshots of caspase-2 in different catalytic states, shedding light on the mechanism of capase-2 activation, substrate binding, and catalysis. By comparing the apo and inhibited caspase-2 structures, we propose that the disruption of a non-conserved salt bridge between Glu-217 and the invariant Arg-378 is important for the activation of caspase-2. These findings broaden our understanding of caspase-2 substrate specificity and catalysis.

A novel catalyst of Ni,W-surface-Ti-rich-ETS-10/Al2O3: Its role and potential of HDS performance for steric hindered sulfur compound 4,6-DMDBT

Formation energies and mechanisms, autoreduction and methane C–H reactivities were obtained for [Cu–O–M]2+species (M = Ti–Cu, Zr–Mo and Ru–Ag) in mordenite with DFT. These reveal that [Cu2O]2+is best suited for MMC.

Study of hydrotreating performance of trimetallic NiMoW/Al2O3 catalysts prepared from mixed MoW Keggin heteropolyanions with various Mo/W ratios