Excitation dependent light emission and enhanced photocatalytic response of WS2/C-dot hybrid nanoscale systems

A facile, hydrothermal route has been employed to synthesize two dimensional (2D) WS2 nanosystems, followed by decoration with C-dots derived from the orange juice extract as the source of carbon. Imaging through transmission electron microscopy (TEM) reveals the formation of C-dots on the WS2 sheets, with dot size varying between 2 and 5 nm and d-spacing of 0.31 nm. The WS2/C-dot hybrid nanosystems were found to reveal excitation dependent luminescence response with underlying mechanism attributed to the influence of either surface traps or/and prevalent heteroatoms. Moreover, Raman spectra of the nanohybrid exhibited both in-plane optic and out of plane vibronic modes, positioned at similar to 352.8 cm(-1) (E-2g(1)) and 421.7 cm(-1) (A(1g)); apart from two additional peaks, assigned to the D and G bands of the graphitic material. Finally, photocatalytic degradation of methyl orange (MO) and malachite green (MG) were studied under visible light illuminations. While exhibiting a comparatively stronger photoactivity, the MG dye yielded degradation efficiency as high as, similar to 83% and 91% in case of use of bare WS2 nanosheet and WS2/C-dots as nanocatalysts; respectively. The bifunctional candidates would find a special place in advanced material research owing to exhibition of enhanced radiative emission as well as photocatalytic features.