RT Journal Article
T1 Carbon nanotubes as catalysts for wet peroxide oxidation: The effect of surface chemistry
A1 Martín Martínez, María
A1 Machado, Bruno F.
A1 Serp, Philippe
A1 Morales Torres, Sergio
A1 Silva, Adrián M. T.
A1 Figueiredo, José L.
A1 Faria, Joaquim L.
A1 Gomes, Helder T.
AB Three magnetic carbon nanotube (CNT) samples, named A30 (N-doped), E30 (undoped) and E10A20 (selectively N-doped), synthesized by catalytic chemical vapor deposition, were modified by introducing oxygenated surface groups (oxidation with HNO3, samples CNT-N), and by heat treatment at 800 °C for the removal of surface functionalities (samples CNT-HT). Both treatments lead to higher specific surface areas. The acid treatment results in more acidic surfaces, with higher amounts of oxygenated species being introduced on Ndoped surfaces. Heat-treated samples are less hydrophilic than those treated with nitric acid, heat treatment leading to neutral or basic surfaces, only N-quaternary and N-pyridinic species being found by XPS on N-doped surfaces. These materials were tested in the catalytic wet peroxide oxidation (CWPO) of highly concentrated 4-nitrophenol solutions (4-NP, 5 g L−1) at atmospheric pressure, T=50 °C and 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. The high temperature treatment enhanced significantly the activity of the CNTs towards CWPO, evaluated in terms of 4-NP and total organic carbon conversion, due to the increased hydrophobicity of their surface. In particular, E30HT and E10A20HT were able to remove ca. 100% of 4-NP after 8 h of operation. On the other hand, by treating the CNTs with HNO3, the activity of the less hydrophilic samples decreased upon increasing the concentration of surface oxygen-containing functionalities, whilst the reactivity generated inside the opened nanotubes improved the activity of the highly hydrophilic A30 N.
PB Elsevier B.V.
SN 0920-5861
YR 2020
FD 2020-11
LK https://hdl.handle.net/20.500.14352/107177
UL https://hdl.handle.net/20.500.14352/107177
LA eng
NO Maria Martin-Martinez, Bruno F. Machado, Philippe Serp, Sergio Morales-Torres, Adrián M.T. Silva, José L. Figueiredo, Joaquim L. Faria, Helder T. Gomes, Carbon nanotubes as catalysts for wet peroxide oxidation: The effect of surface chemistry, Catalysis Today, Volume 357, 2020, Pages 332-340, ISSN 0920-5861, https://doi.org/10.1016/j.cattod.2019.03.014.
DS Docta Complutense
RD 18 abr 2025