Construction of Bi2S3-BiOBr nanosheets on TiO2 NTA as the effective photocatalysts: Pollutant removal, photoelectric conversion and hydrogen generation.

Novel energy material is the investigation focus to overcome the environment pollution and resource shortage crisis. TiO2 nanotube arrays (TiO2 NTA) could be used for pollutant decomposition, photoelectric conversion and H2, CH4 generation. BiOBr nanosheets were fabricated on TiO2 NTA by a solvothermal deposition method, and then transformed into Bi2S3 nanosheets after the ion exchange reaction. The results revealed that the ion concentration significantly influenced the morphology, microstructure, optical harvesting and photoelectrochemical capacity of Bi2S3-BiOBr/TiO2 NTA. The samples also exhibited high photocatalytic activity for the removal of dyes and Cr(VI), and the excellent photocurrent and photovoltage were obtained under visible light irradiation. The photocatalytic water splitting for hydrogen generation was carried out, and the photocatalytic hydrogen production rate achieved 17.26 µmol·cm-2·h-1. The photocatalyst showed the remarkable stability, and the photocatalytic ability still maintained high level after several repeated photocatalytic cycles. The photocatalytic data indicated that the Bi2S3-BiOBr/TiO2 NTA photocatalyst provided a perfect strategy for the sensitizer deposition on TiO2 NTA and novel approach for the photocatalytic performance improvement.

Surface Engineering of Graphene Composite Transparent Electrodes for High-Performance Flexible Triboelectric Nanogenerators and Self-Powered Sensors.

High-performance transparent and flexible triboelectric nanogenerators (TENGs) based on graphene composite electrodes via surface engineering are proposed and demonstrated. Through modifying the CVD-grown graphene with the conductive polymer poly(3,4-ethylenedioxy-thiophene):polystyrenesulfonate (PEDOT:PSS), composite electrodes with excellent optoelectronic performances were fabricated, which exhibited a high transmittance up to 83.5% and sheet resistance of 85 Ω/□, decreasing from the initial value of 725 Ω/□. As a consequence, the output current density and power of the corresponding TENG were enhanced by 140% to 2.4 µA/cm2 and by 118% to 12 µW, respectively, comparing with the counterpart composed of the pristine graphene electrodes. Furthermore, the composite electrode exhibited an outstanding durability of the physical and electrical characteristics after 10 000 bending cycles and can be readily extended to a large area up to 100 cm2. Such flexible, transparent, stable TENGs pave the way for the application of self-powered body sensors due to their unique characteristics, such as portability, wearability, and human compatibility.