Reduced graphene oxide and PbS nanoparticles co-modified TiO2 nanotube arrays as a recyclable and stable photocatalyst for efficient degradation of pentachlorophenol

Abstract

TiO2 nanotube arrays (TiO2 NTs) were simultaneously modified by reduced graphene oxide (RGO) and PbS nonoparticles (NPs) through a simple one-step electrodeposition process. RGO film is formed on the top surface of TiO2 NTs and PbS NPs showing size less than 20nm are intercalated within the RGO sheets and also dispersed inside/outside walls the TiO2 NTs. Resulting from the synergetic effect of RGO and PbS, the photocatalytic activity of the ternary RGO/PbS-TiO2 NTs photocatalyst far exceeds those of bare TiO2 NTs, the binary RGO-TiO2 NTs and PbS-TiO2 NTs photocatalysts in the degradation of pentachlorophenol (PCP) under simulated solar light. After 120-min irradiation, almost 100% PCP removal is obtained on the RGO/PbS-TiO2 NTs, compared to 61% on bare TiO2 NTs, 76% on RGO-TiO2 NTs, and 86% on PbS-TiO2 NTs. Because the PbS NPs were covered by the RGO sheets, to a certain extent the photocorrosion of PbS was suppressed, and therefore the RGO/PbS-TiO2 NTs photocatalyst shows a good stability relative to the PbS-TiO2 NTs without RGO. This study will inspire better design of advanced photocatalysts with high visible-light photocatalytic activity, easy recovery, and good stability.