Transition metal carbides (TMCs) have emerged as excellent catalyst support for fuel cell applications. They can also be employed as supercapacitors and for efficient fuel production (H-2). Recently, TMCs are being explored as photocatalysts due to the similar electronic configuration as that of the noble metals (Pt, Pd, etc.). But, non availability of semi-conducting characteristics in TMCs hinders the generation of excitons required for the photo oxidation of organic pollutants. In this work, niobium carbide/carbon (NbC/C) nanocomposite has been successfully synthesized at relatively low temperature (700 and 800 degrees C) using cellulose acetate (CA). CA was taken as carbon source to compare the catalytic behavior with the NbC/C nanocomposites obtained with smoked cigarette filters in which cellulose acetate is the main component. In-situ formation of disordered graphitic carbon (g-C) has been observed along with NbCx nanoparticles inducing optically active sites (NbCxOy or NbOz) and resulting in 45.8% photodegradation of methylene blue (MB) dye under household CFL illumination. It has been observed that variation in specific surface area, pore volume and lattice composition (C/Nb ratio) controls the photo- as well as electrocatalytic performance of synthesized NbC/C nanocomposite samples. Higher pore volume and in-lattice carbon leads to higher electrochemical specific surface area and an enhanced electrochemical current density. Further, higher specific surface area and 2D g-C exhibited efficient charge transfer responsible for significant hydrogen evolution reaction (HER) activity with lower Tafel slope (110.91 mV/dec) and higher current density (4.77 mA/cm(2)).