Supported Pt-particles on multi-walled carbon nanotubes with controlled surface chemistry

Multi-walled carbon nanotubes (MWCNTs) were functionalized by HNO3 hydrothermal oxidation at 200 °C. The degree of surface functionalization was described by an exponential function in terms of HNO3 concentration. Very small Pt particles, with mean particle size of 1.7 ± 0.3 nm, could be supported on the surface of pristine MWCNTs and also on MWCNTs treated with HNO3 concentrations up to 0.20 mol L− 1, while a broader range of particle sizes, and larger Pt particles (3.4 ± 1.3 nm) were obtained on the MWCNTs treated with a higher HNO3 concentration (0.30 mol L− 1). Therefore, the amounts of surface groups and Pt particle sizes can be selected by tuning the HNO3 concentration used in the hydrothermal treatment.

Pt particle size distribution on pristine MWCNTs and 0.30 mol L− 1 HNO3 treated MWCNTs.Figure optionsDownload as PowerPoint slideHighlights
► Controlled functionalization of MWCNTs by HNO3 hydrothermal oxidation.
► Effect of degree of oxidation on the textural and surface properties.
► Effect of degree of oxidation on the particle size of supported Pt.