Structural, spectral, morphological, thermal and hydrogen storage properties of the multi walled carbon nanotubes functionalized with SnO2 particles (MWCNT/SnO2) heat treated at 300, 350 and 400 degrees C in air were systematically investigated. X-ray diffraction from (110), (101) and (211) planes of SnO2, (002) plane of MWCNT and shift towards higher angle confirmed the formation of composites. XPS, Raman, FTIR and TGA analyses revealed that C-O bond on the surface of MWCNT acts as the nucleation sites for SnO2 which resulted in a strong interaction between MWCNT and SnO2. Presence of C, Sn and O was confirmed by EDX and XPS analyses. Hydrogen adsorption was carried out using hydrogenation set-up and H-2 adsorption/desorption behavior of the composites were studied employing Raman and thermogravimetric analyses. Size, morphology and interaction between MWCNT and SnO2 were impacted significantly by the heat treatment which resulted in high hydrogen storage capacity of 2.13 and 2.62 wt % for 15 and 30 min hydrogenation time for the nanocomposite heat treated at 400 degrees C. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.