The influence of potassium doping on hydrogen adsorption on carbon nanocone material studied by thermal desorption and photoemission

Hydrogen adsorption/desorption on potassium doped carbon nanocones was studied by temperature programmed desorption (TPD), X-ray photoelectron spectroscopy, and ultraviolet photoelectron spectroscopy. TPD shows that the hydrogen storage was enhanced by up to 40% after potassium doping. Hydrogen adsorption on K-modified carbon nanocone material seems more stable than that on the undoped material. The XPS results indicate that there is charge transfer from potassium to carbon. The C 1s binding energy increases with increased potassium doping and the peak becomes wider. These binding energy shifts may be explained by work function changes related to potassium doping. The K 2p spectra indicate that there are two different local environments for potassium on the carbon cone material.