No abstract

No abstract

The development of high-efficiency photocatalysts is of great importance to realize robust solar-driven CO2 conversion; however, the low carrier separation efficiency and poor light absorption ability usually limit the performance of the photocatalysts. Herein, a hollow In2S3/polymeric carbon nitride (IS/CN) heterojunction was prepared via electrostatic self-assembly and in situ sulfidation under solvothermal conditions. The intimate interfacial contact between the IS and CN facilitates the construction of an effective heterojunction, as demonstrated by X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). The optimized IS/CN-5 sample exhibits a high CO evolution rate of 483.4 μmol g–1 h–1, which is 99 and 6 times as high as that of IS and CN, respectively. The improved charge separation and transfer efficiency, the hollow nanotube structure, and the enhanced CO2 adsorption ability are the reasons for the excellent photocatalytic activity. Besides, a possible photocatalytic mechanism of CO2 reduction by the IS/CN heterojunction was proposed on the basis of the band structures. This work provides an effective and facile strategy to construct hollow semiconductor heterojunctions for photocatalytic applications.

No abstract

A scour monitoring system for subsea pipeline based on active thermometry is proposed in this paper. The temperature reading of the proposed system is based on a distributed Brillouin optical fiber sensing technique. A thermal cable acts as the main component of the system, which consists of a heating belt, armored optical fibers and heat-shrinkable tubes which run parallel to the pipeline. The scour-induced free span can be monitored through different heat transfer behaviors of in-water and in-sediment scenarios during heating and cooling processes. Two sets of experiments, including exposing different lengths of the upper surface of the pipeline to water and creating free spans of various lengths, were carried out in laboratory. In both cases, the scour condition was immediately detected by the proposed monitoring system, which confirmed the system is robust and very sensitive. Numerical study of the method was also investigated by using the finite element method (FEM) with ANSYS, resulting in reasonable agreement with the test data. This brand new system provides a promising, low cost, highly precise and flexible approach for scour monitoring of subsea pipelines.