Abstract
The establishment of a solid-state Z-scheme heterojunction photocatalytic system to efficiently tailor photoinduced charge separation is of great significance to water purification. A structure of metal sulfide nanoparticles, tin monosulfide (SnS) and bismuth sulfide (Bi2S3) in host alumina (Al2O3) was developed by the sol-gel method. FTIR confirmed complete dispersion of SnS and Bi2S3 nanoparticles in Al2O3 having a cubic structure. The band gap energy (E-g) of the ternary nanocomposite was found to be 1.85, 1.68 and 1.10 eV for 4.0, 8.0 and 12.0% bismuth sulfide coupled SnS/Al2O3 respectively. The marked decrease in E-g can be attributed to the tenacious agglomeration among SnS, Bi2S3 and Al2O3. 99.0% methyl orange (MO) removal was achieved with 12.0% bismuth sulfide coupled SnS/Al2O3 due to efficient and quick charge transfer among Al2O3 and chalcogenides via Z-scheme electron transfer mechanism. Electrochemical measurements such as those of linear sweep voltammetry and cyclic voltammetry manifested that bismuth sulfide coupled SnS/Al2O3 exhibited several times more current density than pristine Al2O3 which is very well corroborated with the photocatalytic analysis. Investigation of radical scavengers manifested that O-2(-) and OH have important roles in the degradation of MO. This innovative and uniquely designed hybrid ternary nanocomposite will open new horizons as an economical and effective material for photocatalysis.