Mesoporous Cu2ZnSnS4 nanoparticle film as a flexible and reusable visible light photocatalyst

In this work, sintered film of Kesterite structured Cu2ZnSnS4 (CZTS) nanoparticles having size < 15 nm is evaluated for photocatalytic properties. Morphology, crystal structure, composition and optical properties of the CZTS nanoparticles are studied. Brunauer-Emmett-Teller studies showed a specific surface area of similar to 39 m(2)/g with an average pore size of similar to 7 nm. Mesoporous morphology is observed in the fabricated film. CZTS film is prepared on both glass substrate and flexible cotton fabric and used as catalyst for degradation of methylene blue dye under visible light. 90% degradation of dye is observed in an irradiation period of 120 min with an apparent degradation rate constant of similar to 0.029/min. The repeatability studies performed exhibited a standard deviation of 3%. From the analysis of degradation rate under the influence of hole, electron and OH radicals scavengers, it is observed that formation of superoxide radical is the primary reason for degradation of dye. In the base medium, the degradation is found to be faster and in acidic medium it was slow. The work here demonstrates the use of photocatalyst in the form of flexible film enabling roll-to-roll processing.