CO oxidation and the inhibition effects of carboxyl-modification and copper clusters on multi-walled carbon nanotubes

• Published in: Applied catalysis. B, Environmental Environmental, 2020-03, Vol.262, p.118265, Article 118265
• Main Authors: Baharudin, Luqmanulhakim, Yip, Alex C.K., Golovko, Vladimir B., Polson, Matthew I.J., Aguey-Zinsou, Kondo-Francois, Watson, Matthew J.
• Format: Article
• Language: English
• Subjects: Acidic oxides; Air pollution; Carbon dioxide; Carbon monoxide; Carbon nanotubes; Carboxyl groups; Clusters; CO oxidation; Computer simulation; Contaminants; Copper; Copper cluster; Copper converters; Decomposition reactions; Flue gas; Gas streams; Metallurgical constituents; Multi wall carbon nanotubes; Nanotechnology; Nanotubes; Organic chemistry; Oxidation; Pollutants; Polycyclic aromatic hydrocarbons; Reaction inhibition; Stream pollution; Trace metals; Water pollution
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2019.118265

[Display omitted] •CO conversion of >98% was achieved from ∼230 °C using pristine MWCNT as a catalyst.•COOH-modified MWCNT adsorbed significant amounts of CO molecules without converting.•Cu6 clusters initially formed CuCO3 that decomposed above 400 °C to release CO2. An inhibition of CO oxidation on catalytically active pristine multi-walled carbon nanotubes (MWCNT) in the presence of selected pollutant constituents in flue gas streams was studied. We simulated an interaction between the active MWCNT and the contaminants in CO oxidation atmosphere of: (i) an acidic wet flue gas environment modelled by using MWCNT grafted with carboxyl (COOH) groups; and (ii) a polluted environment formed by trace metal copper particles and other contaminant constituents (e.g. PAHs, VOCs and P) by using a copper cluster of chemical formulae [(PPh3)CuH]6·0.75THF as a model pollutant, doped on the MWCNT. The pristine, unmodified MWCNT were catalytically active from ∼150 °C, whilst the carboxyl-modified MWCNT behaved as an adsorbent of CO molecules without converting them into CO2. The copper cluster was found to have formed CuCO3 during the CO oxidation reaction at temperatures below 330 °C but decomposed above 400 °C to release CO2 product.