Synthesis and characterization of Pd-Ni catalysts supported on KIT-6 and their application in cyclohexane oxidation using molecular oxygen

Mesoporous SO42- / kit-6-catalyzed hydrocracking of waste chicken oil

In this study, we studied the hydrocracking of waste chicken oil (WCO) catalyzed by mesoporous SO42-/KIT-6. The study included WCO extraction, SO42-/KIT-6 catalyst synthesis, hydrocracking, and catalytic characterization. XRD patterns revealed intense peaks in the low-angle region, with shoulder peaks showing an increase in sulphate loading from 10% to 30%. The BET-specific surface area for the pure KIT-6 supports measured at 1003 m2/g, indicative of a well-defined mesoporous structure. Thermogravimetric analysis (TGA) showed a two-stage weight loss, attributed to the elimination of hydrated water (about 200 °C) and decomposition of sulphate ions (400-450 °C). SEM analysis highlighted the surface morphology of the active SK-2 catalyst. Hydrocatalytic and catalytic cracking reactions were performed, and about 99.8% conversion was achieved with 20 mL/H H2 flow, whereas higher production of bioliquids was observed at a flow of 15 mL/h. The hydrocracking mechanism was also studied to understand the formation of lower hydrocarbons. GC analyses of simulated distilled gasoline, kerosene, and diesel showed diverse hydrocarbon compositions. For engine testing, non-hydrocracked fuel rose to 28 kW at 3000 rpm and declined to 21 kW at 3500 rpm. Emission analysis revealed decreasing trends in NOX emissions of hydrogen-rich blends, with values of 65 ppm, 54 ppm, and 48 ppm for petrol, NHBL, and HBL, respectively. Similarly, SO2 emissions reduced from petrol to NHBL and HBL at 910 ppm, 800 ppm, and 600 ppm, respectively, suggesting reduced environmental impact. CO emissions exhibited a substantial reduction in NHBL (0.90%) and HBL (0.54%) compared to petrol (2.70%), emphasizing the cleaner combustion characteristics. Our results provide a comprehensive exploration of waste chicken oil hydrocracking, emphasizing catalyst synthesis, fuel characterization, engine performance, and environmental impact, thereby contributing valuable insights to the field of sustainable bioenergy.

Efficient Inhibition of Deep Conversion of Partial Oxidation Products in C-H Bonds' Functionalization Utilizing O2 via Relay Catalysis of Dual Metalloporphyrins on Surface of Hybrid Silica Possessing Capacity for Product Exclusion

To inhibit the deep conversion of partial oxidation products (POX-products) in C-H bonds' functionalization utilizing O2, 5-(4-(chloromethyl)phenyl)-10,15,20-tris(perfluorophenyl)porphyrin cobalt(II) and 5-(4-(chloromethyl)phenyl)-10,15,20-tris(perfluorophenyl)porphyrin copper(II) were immobilized on the surface of hybrid silica to conduct relay catalysis on the surface. Fluorocarbons with low polarity and heterogeneous catalysis were devised to decrease the convenient accessibility of polar POX-products to catalytic centers on the lower polar surface. Relay catalysis between Co and Cu was designed to utilize the oxidation intermediates alkyl hydroperoxides to transform more C-H bonds. Systematic characterizations were conducted to investigate the structure of catalytic materials and confirm their successful syntheses. Applied to C-H bond oxidation, not only deep conversion of POX-products was inhibited but also substrate conversion and POX-product selectivity were improved simultaneously. For cyclohexane oxidation, conversion was improved from 3.87% to 5.27% with selectivity from 84.8% to 92.3%, which was mainly attributed to the relay catalysis on the surface excluding products. The effects of the catalytic materials, product exclusion, relay catalysis, kinetic study, substrate scope, and reaction mechanism were also investigated. To our knowledge, a practical and novel strategy was presented to inhibit the deep conversion of POX-products and to achieve efficient and accurate oxidative functionalization of hydrocarbons. Also, a valuable protocol was provided to avoid over-reaction in other chemical transformations requiring high selectivity.

Plasmonic photocatalytic nanocomposite of in-situ synthesized MnO2 nanoparticles on cellulosic fabric with structural color

The textile industry produces 20 % of the industrial water pollution containing toxic substances mostly dyes. Reducing material consumption and developing more efficient and scalable textile waste-water treatment methods such as photocatalytic degradation is essential. In this work, manganese dioxide nanoparticles (MnO2 NPs) were synthesized on the cotton fabric via a facile in-situ process. The preparation process was optimized for the highest photocatalytic activity under sunlight and color change originating from the plasmonic structural color of the nanoparticles. This promotes the photocatalytic activity by delocalization of the hot electrons while demonstrating the best washing and light fastness by using the least chemicals, and energy in a short time. In this way, the fabric was colored without any dye and possessed robust photocatalytic activity. Further, no dye-containing waste-water is made, and also accomplished to degrade dyes in a few hours under sunlight which is substantial for sustainable development. The treated fabrics indicated favorable mechanical properties, enhanced thermal stability, and perfect biocompatibility.

Efficient and Selective Oxygenation of Cycloalkanes and Alkyl Aromatics with Oxygen through Synergistic Catalysis of Bimetallic Active Centers in Two-Dimensional Metal-Organic Frameworks Based on Metalloporphyrins

Confined catalytic realms and synergistic catalysis sites were constructed using bimetallic active centers in two-dimensional metal-organic frameworks (MOFs) to achieve highly selective oxygenation of cycloalkanes and alkyl aromatics with oxygen towards partly oxygenated products. Every necessary characterization was carried out for all the two-dimensional MOFs. The selective oxygenation of cycloalkanes and alkyl aromatics with oxygen was accomplished with exceptional catalytic performance using two-dimensional MOF Co-TCPPNi as a catalyst. Employing Co-TCPPNi as a catalyst, both the conversion and selectivity were improved for all the hydrocarbons investigated. Less disordered autoxidation at mild conditions, inhibited free-radical diffusion by confined catalytic realms, and synergistic C-H bond oxygenation catalyzed by second metal center Ni employing oxygenation intermediate R-OOH as oxidant were the factors for the satisfying result of Co-TCPPNi as a catalyst. When homogeneous metalloporphyrin T(4-COOCH3)PPCo was replaced by Co-TCPPNi, the conversion in cyclohexane oxygenation was enhanced from 4.4% to 5.6%, and the selectivity of partly oxygenated products increased from 85.4% to 92.9%. The synergistic catalytic mechanisms were studied using EPR research, and a catalysis model was obtained for the oxygenation of C-H bonds with O2. This research offered a novel and essential reference for both the efficient and selective oxygenation of C-H bonds and other key chemical reactions involving free radicals.