Preparation of stable metal/COOH-MWCNT hybrid nanofluid

Multiwall carbon nanotube (MWCNT) nanofluid have potential to deliver high rate of heat transfer due to the presence of MWCNT which are having high thermal conductivity. Dispersion of MWCNT in polar basefluid is a difficult task because MWCNT are hydrophobic in nature which makes their utilization as a heat transfer fluid challenging. Metal nanoparticles can be attached with MWCNT which can possibly improve their dispersion. These nanofluid are called as hybrid nanofluid. The present study investigates the dispersion stability of hybrid of COOH-functionalized multi-walled carbon nanotubes (COOH-MWCNT) with different metals such as silver (Ag/COOH-MWCNT), copper (Cu/COOH-MWCNT), iron (Fe/COOH-MWCNT) and zinc (Zn/COOH-MWCNT) dispersed in distilled water as a basefluid. Chemical reduction method was used to synthesize hybrid nanoparticles by reducing metal cations in the presence of MWCNT. Dispersion of hybrid metal-MWCNT hybrid has been investigated by spectra analysis method (UV–Vis spectrophotometer) and zeta potential. Scanning electron microscope imaging with EDAX confirmed distribution of metal nanoparticle on the MWCNT surface. Thermal conductivity was measured using KD2 pro thermal analyzer. Results revealed that the sequence of dispersion stability and thermal conductivity of prepared nanofluid was Cu/COOH-MWCNT > Fe/COOH-MWCNT > Ag/COOH-MWCNT > Zn/COOH-MWCNT in distilled water.