Ivar Kruusenberg

Hydrodynamic Deposition of Carbon Nanotubes onto HOPG: The Reduction of Oxygen on CNT/HOPG Electrodes in Alkaline Solution

The electrochemical reduction of oxygen on highly oriented pyrolytic graphite (HOPG) electrodes coated with multiwalled carbon nanotubes (MWCNTs) was investigated in alkaline media using the rotating disk electrode (RDE) technique. A hydrodynamic method was employed for the deposition of nanotubes onto HOPG. The surface morphology of the MWCNT-modified HOPG electrodes was examined by atomic force microscopy. RDE studies indicate that the MWCNT/HOPG electrodes reveal a remarkable electrocatalytic activity toward O 2 reduction, and the surface morphology of the modified electrodes showed that the distribution of nanotubes on the HOPG surface was rather uniform and no essential agglomeration was evident.

Enhanced electrocatalytic activity of nitrogen-doped multi-walled carbon nanotubes towards the oxygen reduction reaction in alkaline media

In this work multi-walled carbon-nanotubes (MWCNTs) were doped with nitrogen using cyanamide (CM) or dicyandiamide (DCDA). To incorporate nitrogen into the CNT structure, high-temperature pyrolysis in an inert atmosphere was performed. For surface characterisation of nitrogen-doped CNTs (NCNTs) X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used. According to the results of XPS analysis, nitrogen was successfully incorporated into the carbon nanotube network. The electrocatalytic activity of NCNT catalysts for oxygen reduction reaction (ORR) in alkaline media was examined using the rotating disk electrode (RDE) and linear sweep voltammetry (LSV) measurements. The NCNT-DCDA material showed a better ORR performance than the NCNT-CM catalyst. The RDE results reveal that the NCNT materials studied could be considered as interesting alternatives to Pt-based catalysts in alkaline membrane fuel cells.

Nano-electrocatalyst materials for low temperature fuel cells: A review

Abstract Low temperature fuel cells are an attractive technology for transportation and residential applications due to their quick start up and shut down capabilities. This review analyzed the current status of nanocatalysts for proton exchange membrane fuel cells and alkaline membrane fuel cells. The preparation process influences the performance of the nanocatalyst. Several synthesis methods are covered for noble and non-noble metal catalysts on various catalyst supports including carbon nanotubes, carbon nanofibers, nanowires, and graphenes. Ex situ and in situ characterization methods like scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and fuel cell testing of the nanocatalysts on various supports for both proton exchange and alkaline membrane fuel cells are discussed. The accelerated durability estimate of the nanocatalysts, predicted by measuring changes in the electrochemically active surface area using a voltage cycling method, is considered one of the most reliable and valuable method for establishing durability.