KIT-6 Three Dimensional Template Derived Mesoporous Carbon for Oxygen Reduction Reaction: Effect of Template Removal on Catalytic Activity

Non precious highly ordered mesoporous carbon (OMC) is of indomitable and perennial catalyst in fuel cells owing to their unique traits and abundant sources. The OMC has been synthesized using KIT-6 sacrificial template and then this removed by three different etching agents, viz, hydrofluoric acid (HF), sodium hydroxide (NaOH) and polyvinylidene fluoride (PVDF). The principle aim of the present work is that to inspect the etched OMCs for oxygen reduction reaction (ORR) activity. In order to understand the effect of etching, we have first studied their fundamental properties. Among three, the HF etched OMC possess comparative surface area (234 m(2) g(-1)), mesoporous sizes (6 nm), large pore volumes (0.13 cm(3) g(-1)) and more accessible defective active sites (I-D/I-G = 0.90). Hence, the HF etched OMC replica manifest better ORR activity than others in terms of having (0.83 V) onset and (0.71 V) half wave potential, and (2.6 mA/cm(2) at 0.2 V) current density in potassium hydroxide (KOH) electrolyte. From the Nyquist plot, a small semicircle (R-ct = 13 omega cm(-2)) of HF etched OMC substantiates its better ORR activity. A comparative study on etching of OMC using different etching agents could guide to find out a suitable etching agent for modifying the surface properties of OMC.