Metal−organic frameworks (MOFs) are extensively used in catalysis due to their robust structure, well-defined periodic reaction centers, and high porosity. We report Cu 3 (BTC) 2 •(H 2 O) 3 (HKUST-1) as an efficient heterogeneous catalyst for aziridination of alkene and ring-opening reaction of activated aziridines. Furthermore, we demonstrate that the transfer of a nitrogen group from PhINTs to olefins and its analogue to give aziridines takes place at the coordinatively unsaturated Cu(II) site of Cu 3 (BTC) 2 −MOF; however, the ring opening of activated aziridines is controlled by the Cu(II) Lewis acid site, and generation of coordinative unsaturation by thermal activation of the MOF is not necessarily important. The key advantage of this catalytic approach is the direct formation of C−C, C−N, C−O, and C−S bonds yielding β-aryl sulfonamide derivatives through a simultaneous aziridination ring-opening reaction of the alkene in one pot using a single catalyst.

A new, easy and green method is utilized for producing silver decorated graphene for its application in sensors and supercapacitors. The biomass-derived silver decorated graphene (AgGr) samples are prepared using an APCVD reactor with varying the process temperature from 600 to 800 °C. The as-synthesized AgGr samples were then characterized by AFM, SEM, Raman spectroscopy, FTIR spectroscopy, XRD, cyclic voltammetry and impedance spectroscopy. The interlayer spacing and ID/IG ratio of the AgGr samples varied from 3.6 to 3.7 Å and 0.87 to 1.52, respectively, as the process temperature was raised from 600 to 800 °C. The SEM image shows the distribution of the flower-like structure of Ag flakes in the graphene sheet for the AgGr-800 sample. Also, the greater number of active sites on the surface of AgGr-800 and the presence of a higher number of defects makes it least useful for p-nitrophenol sensing due to the excess opening of the CV curve but has a maximum capacitance of 93.5 Fg−1 in 1 M H2SO4. AgGr-600 showed extremely good sensing of p-nitrophenol than the other AgGr samples. Therefore this novel technique can be utilized for the large scale manufacture of various metal decorated graphene samples for their application in different fields.

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The sluggish oxygen reduction reaction (ORR) at the cathode is challenging and hinders the growth of hydrogen fuel cells. Concerning kinetic values, platinum is the best known catalyst for ORR; however, its less abundance, high cost, and corrosive nature warrant the development of low-cost catalysts. We report the hydrothermal synthesis of two novel Mn-based metal− organic frameworks (MOFs), [Mn 2 (DOT)(H 2 O) 2 ] n (Mn-SKU-1) and [Mn 2 (DOT) 2 (BPY) 2 (THF)] n (Mn-SKU-2) (DOT = 2,5dihydroxyterephthalate; BPY = 4,4′-bipyridine). Mn-SKU-1 contains dimeric Mn(II) centers where the two corner-shared MnO 6 octahedra fuse to give rise to an infinite Mn 2 O 10 cluster, whereas the two Mn(II) ions coordinate to DOT and BPY moieties to give rise to a pillared structure in Mn-SKU-2 and form a 3D → 3D homo-interpenetration MOF with a twofold interpenetrated net. The pyrolysis of as-synthesized Mn-MOFs at 600 °C under N 2 produced exclusively porous α-Mn 2 O 3 composites (PSKU-1 and PSKU-2), with the BET surface area of 90.8 (for PSKU-1) and 179.3 m 2 g −1 (for PSKU-2). These mesoporous MOF-derived α-Mn 2 O 3 composites were modified as cathode materials for the electrocatalytic reduction of oxygen. The onset potential for the oxygen reduction reaction was found to be 0.90 V for PSKU-1 and 0.93 V for PSKU-2 versus RHE in 0.1 M KOH solution, with the current density of 4.8 and 6.0 mA cm −2 , respectively, at 1600 rpm. Based on the RDE/RRDE results, the electrocatalytic oxygen reduction occurs majorly via the four-electron process. The electrocatalyst PSKU-2 is cheap, easy to use, retains 90% of its activity after 10 h of continuous use, and offers higher recyclability than Pt/C. The onset potential maximum current density and kinetic values (J k = 11.68 mA cm −2 and Tafel slope = 85.0 mV dec −1 ) obtained in this work are higher than the values reported for pure Mn 2 O 3 .