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From waste to value: electrocatalytic reduction of nitrate into ammonia at mono...
Ferreira, Marta; Kuzniarska-Biernacka, Iwona; Soares, Olívia S. G. P.; Figueiredo, José L.; Pereira, Manuel F. R.; Neves, Isabel C.; Fonseca, A. M.The electrochemical transformation of nitrate ions into ammonia (NH3), which ranks among the most widely employed chemicals globally, using mono (Pd, Pt) and bimetallic catalysts (Pd-Cu, Pt-Cu, Ru-Cu) supported on carbon nanotubes (CNT) was studied in acidic medium. The higher conversion and best selectivity towards NH3 corresponding, respectively, to 88 and 80% were found for Pt_CNT modified electrode, with an...
Porphyrin–Nanodiamond Hybrid Materials—Active, Stable and Reusable Cyclohexene ...
Dias, Lucas Danilo; Rodrigues, Fábio M.S.; Calvete, Mário J. F.; Carabineiro, Sónia A. C.; Scherer, Marisa D.; Caires, Anderson R. L.The quest for active, yet “green” non-toxic catalysts is a continuous challenge. In this work, covalently linked hybrid porphyrin–nanodiamonds were prepared via ipso nitro substitution reaction and characterized by X-ray photoelectron spectroscopy (XPS), fluorescence spectroscopy, infrared spectroscopy (IR) and thermogravimetry-differential scanning calorimetry (TG-DSC). The amine-functionalized nanodiamonds (N...
Electrochemical oxidation of amoxicillin on carbon nanotubes and carbon nanotub...
Ferreira, Marta; Kuzniarska-Biernacka, Iwona; Fonseca, António; Neves, Isabel C.; Soares, Olívia S. G. P.; Pereira, Manuel F. R.; Figueiredo, José L.The electrolysis of amoxicillin (AMX) was carried out on CNT, Pt/CNT and Ru/CNT modified electrodes based on Carbon Toray in 0.1 M NaOH, 0.1 M NaCl and 0.1 M Na2CO3/NaHCO3 buffer (pH 10) media with the aim of studying the significance of two factors, electrode material and pH, on the oxidative degradation and mineralization of AMX. For this purpose, the electrolysis products were identified by HPLC-MS and GC-MS...
Supported C-Scorpionate Vanadium(IV) Complexes as Reusable Catalysts for Xylene...
Wang, Jiawei; Martins, Luisa; Da Costa Ribeiro, Ana Paula; Carabineiro, Sonia Alexandra Correia; Figueiredo, José L.; Pombeiro, ArmandoC-Scorpionate vanadium(IV) [VOxCl3-x{k(3)-RC(pz)(3)}] [pz = pyrazol-1-yl; x=0, R = SO3 (1); x = 1, R= CH2OH (2) or CH2OSO2Me (3)] complexes supported on functionalized carbon nanotubes (CNTs) are the first V-scorpionate catalysts used so far for the neat oxidation of o-, m- or p-xylene, with TBHP (70% aqueous solution), to the corresponding toluic acids (main products), tolualdehydes and methylbenzyl alcohols. ...
Oxidovanadium(V) complexes anchored on carbon materials as catalysts for the ox...
Sutradhar, Manas; Martins, Luisa; Carabineiro, Sónia A. C.; Guedes Da Silva, M. Fátima C.; Buijnsters, Josephus; Figueiredo, José L.; Pombeiro, ArmandoSix oxidovanadium(V) aroylhydrazone complexes derived from (3,5-di-tert-butyl-2-hydroxybenzylidene)-2-hydroxybenzohydrazide (H2L1) and (3,5-di-tert-butyl-2-hydroxybenzylidene)-2-aminobenzohydrazide (H2L2), namely, [VOL1(OEt)][VOL1(OEt) (EtOH)] (1), [VOL2(OEt)] (2), [Et3NH][VO2L1] (3), [VO2(HL2)]center dot 2EtOH (4), [(VOL1)(2)(mu-O)] (5), and [(VOL2)(2)(mu-O)] (6), were synthesized and characterized by elementa...
Characterization of Active Sites on Carbon Catalysts
Figueiredo, José L.; Pereira, Manuel F. R.; Freitas, Maria M. A.; Órfão, José J. M.A method based on the deconvolution of TPD spectra is proposed for the characterization of surface oxygen groups, which can act as the active sites on carbon catalysts. The method, which was previously used to characterize activated carbons oxidized in the gas phase, has been extended and applied to other materials, carbons oxidized in the liquid phase. It is shown that this method fits quite well the TPD exper...