Synthesis of $$\hbox {Ag}_{2}\hbox {Se}$$ Ag 2 Se –graphene– $$\hbox {TiO}_{2} $$ TiO 2 nanocomposite and analysis of photocatalytic activity of $$\hbox {CO}_{2}$$ CO 2 reduction to $$\hbox {CH}_{3}\hbox {OH}$$ CH 3 OH

The present work deals with the development of a new ternary composite, $$\hbox {Ag}_{2}\hbox {Se}$$ – $$\hbox {G}$$ – $$\hbox {TiO}_{2}$$ , using ultrasonic techniques as well as X-ray diffraction (XRD), scanning electron microscopy (SEM), high transmission electron microscopy (HTEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and UV–Vis diffuse reflectance spectra (DRS) analyses. The photocatalytic potential of nanocomposites is examined for $$\hbox {CO}_{2}$$ reduction to methanol under ultraviolet (UV) and visible light irradiation. $$\hbox {Ag}_{2}\hbox {Se}$$ – $$\hbox {TiO}_{2}$$ with an optimum loading graphene of 10 wt% exhibited the maximum photoactivity, obtaining a total $$\hbox {CH}_{3}\hbox {OH}$$ yield of 3.52  $$\upmu \hbox {mol}\,\hbox {g}^{-1}\,\hbox {h}^{-1}$$ after 48 h. This outstanding photoreduction activity is due to the positive synergistic relation between $$\hbox {Ag}_{2}\hbox {Se}$$ and graphene components in our heterogeneous system.