Influence of pre-oxidation, versus post-oxidation of carbon nanohorns in TiO2 nanohybrid for enhanced photocatalytic hydrogen production

Carbon nanohorns were prepared using Arc discharge method in an open air at stationary cathode. Nanohybrids of carbon nanohoms/titania were synthesized by wet impregnation method followed by thermal oxidation in air at 520 degrees C for 30 min. Alternatively, pre-oxidized carbon nanohoms were prepared at the same conditions to examine any change in surface properties. Nanohybrids were subjected to characterization for its structure, morphology, optical properties and life-time of photogenerated electrons and holes. The photocatalytic performance of the two nanohybrids activated by solar light confirmed that pre-oxidized catalyst showed superior performance followed by post-oxidised and pristine catalyst. Hence, present study delineates the benefits of preoxidation process that generated nanowindows morphology on carbon surface that facilitated increased generation, effective utilization and minimizes the recombination of electron-hole pairs in-turn triggered enhanced hydrogen production.