Photocatalytic activity and stability of the ZnO-GO composite thin films

Abstract

This study investigates the photocatalytic activity and long-term stability of a two layered Vis-active composite thin films ZnO/ZnO-GO: (a) under UV+VIS irradiation (55W/m2) and (b) under 100% UV (3W/ m2), for up to 48 h, using methylene blue (c = 10 ppm) as standard pollutant. The photocatalysts stability is discussed considering the variation in transmittance and roughness (RMS) before/after photocatalysis correlated with the processes affecting the photocatalyst surfaces. The photo-degradation efficiencies reach 98% after 48h under UV+VIS irradiation for the thin film sprayed on a thinner ZnO layer; that was also the mostly stable film, with low transmittance (<10 %) and RMS (<10 nm) variations before/after 48 h of UV+VIS irradiation.