Role of Nitrogen Doping on the Performance of Carbon Nanotube Catalysts: A Catalytic Wet Peroxide Oxidation Application

Martín Martínez, MaríaRibeiro, Rui S.Machado, Bruno F.Serp, PhilippeMorales Torres, SergioSilva, Adrián M. T.Figueiredo, José L.Faria, Joaquim L.Gomes, Helder T.2024-07-302024-07-302016-06-15Martin‐Martinez, Maria, et al. «Role of Nitrogen Doping on the Performance of Carbon Nanotube Catalysts: A Catalytic Wet Peroxide Oxidation Application». ChemCatChem, vol. 8, n.o 12, junio de 2016, pp. 2068-78. DOI.org (Crossref), https://doi.org/10.1002/cctc.201600123.1867-38801867-389910.1002/cctc.201600123https://hdl.handle.net/20.500.14352/107216Four magnetic carbon nanotube (CNT) samples (undoped, completely N-doped, and two selectively N-doped) were synthesized by chemical vapor deposition. The materials were tested in the catalytic wet peroxide oxidation (CWPO) of highly concentrated 4-nitrophenol solutions (4-NP, 5 g L−1). Relatively mild operating conditions were considered (atmospheric pressure, T=50 °C, pH 3), using a catalyst load of 2.5 g L−1 and the stoichiometric amount of H2O2 needed for the complete mineralization of 4-NP. N-doping was identified to influence considerably the CWPO performance of the materials. In particular, undoped CNTs, with a moderate hydrophobicity, favor the controllable and efficient decomposition of H2O2 into highly reactive hydroxyl radicals (HO.), thus showing high catalytic activity for 4-NP degradation. On the other hand, the completely N-doped catalyst, fully hydrophilic, favors a quick decomposition of H2O2 into nonreactive O2 and H2O species. The selectively N-doped amphiphilic catalysts, that is, hybrid structures containing undoped sections followed by N-doped ones, provided intermediate results, namely, a higher N content favored H2O2 decomposition towards nonreactive H2O and O2 species, whereas a lower N content resulted in the formation of HO., increasing 4-NP mineralization. Catalyst stability and reusability were also investigated by consecutive CWPO runs.engAttribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/Role of Nitrogen Doping on the Performance of Carbon Nanotube Catalysts: A Catalytic Wet Peroxide Oxidation Applicationjournal articlehttps://doi.org/10.1002/cctc.201600123https://chemistry-europe.onlinelibrary.wiley.com/doi/full/10.1002/cctc.201600123open access66544.47Ingeniería química3303 Ingeniería y Tecnología Químicas3303.01 Tecnología de la Catálisis