Easy synthesis of porous carbon mesospheres and its functionalization with titania nanoparticles for enhanced field emission and photocatalytic activity

A simple low temperature chemical approach for synthesizing porous carbon microspheres and its hybrid structure with titanium dioxide (TiO₂) nanoparticle is reported. The carbon spheres and related hybrid structures were characterized by X-ray diffraction, scanning and transmission electron microscopy, Raman and UV–Vis–NIR spectroscopy. The microscopic studies confirm the successful synthesis of hybrid structure of carbon spheres with TiO₂ nanoparticles. Also it reveals that the porous carbon spheres were actually composed of few layers thick carbon flakes. The performance of these as-synthesized pure and hybrid materials on removal of poisonous dyes from water under photon irradiation was studied. It is found that the hybrid sample shows better photocatalytic activity. It is also shown that TiO₂ nanoparticle functionalization enhances the electron field emission properties of carbon sample with reduction of turn-on field from 5.1 to 3.4 V/μm. The enhancement in the photocatalytic activity is due to the combined effect of higher surface area and the injection of electrons from carbon to TiO₂ nanoparticles whereas in case of field emission TiO₂ particles act as additional sites with lower work function and increase the roughness helping enhancement of field strength giving enhanced emission. - Highlights: • Carbon microspheres made of carbon sheet were synthesized by chemical route. • The as synthesized carbon structure has been functionalized with TiO₂ particles. • Hybrid samples show enhanced photocatalytic activity compared to pure sample. • Hybrid sample shows better field emission for an optimized amount of TiO₂ particle.