Abstract: Formic acid (FA) is widely known and recognized as a safe and convenient hydrogen carrier. Accordingly, the development of active and cost effective catalysts for converting FA into hydrogen is one of the key goals in the hydrogen energy field. Herein, we have investigated the catalytic properties of Co nanoparticles supported on oxidized multi-walled carbon nanotubes (MWCNTs Ox), with regard to the gas-phase decomposition of FA. Various parameters of the catalysts such as Co loading, MWCNTs structure, and nanotubes treatment conditions, have been investigated in terms of their influence on the catalytic properties. In situ XRD, TPR and HRTEM have reliably established the influence of each of the studied parameters on the morphology and distribution of Co nanoparticles in the structure of MWCNTs and their catalytic properties in the decomposition of FA. It was shown that the increase of Co loading from 3.5 to 14.5 wt.% in the samples led to different distribution of nanoparticles in the MWCNTs structure. With 3.5–7.5 wt.% of cobalt loading, the main part of the particles was inside the MWCNT channels with an average particle size equal to their inner diameter, which is 4 nm. Further increase in Co loading led to a growth in the amount of particles located on the MWCNTs outer surface with an average diameter being about 20 nm. The study of the catalytic activity showed that an increase in Co loading from 3.5 to 14.5 wt.% led to an increase in activity, which apparently due to various localization of Co nanoparticles. For 14.5% Co/MWCNT Ox sample about 80% of the particles were located on the outer surface and complete conversion of FA was observed at a temperature of 240 °C. Additional mechanochemical treatment of MWCNT Ox allowed to redistribute a larger number of particles with Co loading of 14.1 wt.% into the internal channels of nanotubes. However, the latter resulted in a decrease in catalytic activity in the FA decomposition reaction.

Cite: Kazakova M.A. , Selyutin A.G. , Koltunov K.Y. , Sobolev V.I.
Co/multi-walled Carbon Nanotubes as Highly Efficient Catalytic Nanoreactor for Hydrogen Production from Formic Acid
2021 International Chemical Congress of Pacific Basin Societies 16 Nov - 21 Dec 2021