Designing a new reaction system by stacking use of Ti mesh supported Ag/N-TiO2 nano-sheets for enhanced photocatalytic degradation of bisphenol A

Abstract

In this work, Ag nano-particles deposited and N-doped TiO2 nanosheets grown on the Ti mesh (Ag/N-TiO2/Ti mesh) were synthesized through combination of a hydrothermal process and a photo-reduction deposition strategy, and then applied to photocatalytic (PC) degradation of bisphenol A (BPA). The physicochemical performances of Ag/N-TiO2/Ti mesh were investigated by a series of characterizations. Results showed that N doping promoted the formation of rutile, and increased the thickness of TiO2 nanosheets (30 nm–40 nm). Furthermore, N element was existed in the form of substitutional nitrogen state (O-Ti-N) in the lattice of TiO2, generating N2p doping energy level. The Ag nanoparticles were deposited on the surface of N-TiO2 in the form of Ag0. The PC removal efficiency of BPA by Ag/N-TiO2/Ti mesh was 90.5% within 60 min, much higher than that of N-TiO2/Ti mesh (78.0%) and TiO2/Ti mesh (59.5%). The N adulteration and surfaceplasmaresonance of Ag0 significantly enhanced the visible-light absorbance and photo-excited electrons-holes separation, which accounted for the improved PC degradation of BPA. By using the light transmittance performance of Ti mesh to stack three Ag/N-TiO2/Ti mesh (named 3-Ag/N-TiO2/Ti mesh) in a distance interval of 0.5 cm constructed a new reaction system, and it removed over 99.99% of BPA within 30 min, which was significantly higher than that of Ag/N-TiO2/Ti mesh system (59.5%). This was mainly ascribed to the effective optical energy utilization and the enhanced mass transfer. This study not only indicated that Ag/N-TiO2/Ti mesh was a promising photocatalyst, but also offered useful information for designing specific reactor in practical application (such as amplified cylindrical reactor).