Ultrasonic assisted coating of multiwalled carbon nanotubes with NiFe-layered double hydroxide for improved electrocatalytic oxygen reduction

Due to its good electronic conductivity and large specific surface area, multiwalled carbon nanotube (MWCNT) has been proven a good platform for the further fabrication of efficient oxygen reduction reaction (ORR) catalysts. In this work, the nanocomposite of NiFe layered double hydroxides (NiFe-LDHs) and MWCNT was synthesized by the direct coating of MWCNT with NiFe-LDH nanoparticles (NPs) under ultrasonic assistance. It was found out that MWCNT can be easily dispersed in the NiFe-LDH suspension. The dispersed MWCNT was simultaneously coated with NiFe-LDH NPs via the electrostatic interaction between the negatively charged MWCNT and positively charged NiFe-LDH NPs. The obtained nanocomposite (NiFe-LDH/MWCNT) exhibits tube-like structure and good dispersity in polar solvents such as ethanol and water. Further investigation shows that NiFe-LDH/MWCNT possesses excellent ORR activity with 4e-route selectivity, suggesting the synergistic effect between NiFe-LDH and MWCNT. Moreover, NiFe-LDH/MWCNT exhibited improved catalytic capability and durability than commercial Pt/C catalysts.