DangSheng Su and colleagues from the Fritz-Haber Institute in Berlin studied the dynamic changes and thermal stability of nitrogen functional groups attached to Carbon Nanotubes (CNTs), for the rational design of basic CNT catalysts. 

CNTs with either basic or acidic properties have the potential to be used as a greener alternative to transition metal catalysts, explains Su. The addition of nitrogen groups was chosen in order to create CNTs with basic properties, however it is important to determine what happens to those nitrogen-containing groups at higher temperatures. 

The scientists determined, using Temperature Programmed X-ray Photoelectron Spectroscopy with on-line Mass spectrometry, that it was possible to correlate changes with temperature: they found that some of the nitrogen functionalities initially present in the sample were released into the gas phase (with consequent decrease in the overall nitrogen content) and some functional groups were retained, undergoing dynamic surface rearrangement during heating. 

Su explains that the correlation between temperature and the distribution of the surface functional groups remaining on the CNT surface makes it possible to tune the acidic / basic properties of the products, making it possible to produce products with different levels of basicity for different purposes. 

Rachel Cooper