Ag and Au nanoparticles decorated on synthetic clay functionalized multi-walled carbon nanotube for oxygen reduction reaction

A novel clay (aminoclay, AC) functionalized multi-walled carbon nanotube (MWCNT) was employed as a novel hybrid supporting material to Ag and Au nanoparticles for the improvement of oxygen reduction reaction (ORR). The size and structure of the catalysts were studied by XRD and electron microscopy analysis, revealing that the average crystallite and particle size was about 3.4 and 2.6 nm for Au and 16.2 and 15.3 nm for Ag nanoparticles, respectively. The ORR performance was probed by employing the voltammetry techniques under static and hydrodynamic conditions. The results show that the electrochemical surface area of Au (57.5 m 2 /g) and Ag (17.8 m 2 /g) on AC/MWCNT are larger than that of AC-free catalysts, and the ORR mechanism follows a direct 4-electron transfer pathway. The supported Au and Ag on AC/MWCNT catalysts explicitly showed the enhanced electrocatalytic efficiency and activity on ORR than that of the AC-free MWCNT catalysts. This work demonstrates that developing surface functionalized carbon support using an inorganic silicate layer (clay minerals) as hybrid support for the persistence of active metal catalysts could be a promising strategy for advanced LT-AFCs ORR electrocatalysts.