Single atomic layer nanosheet materials show great application potential in many fields due to their enhanced intrinsic properties compared to their counterparts and newly born properties. Herein, g-C 3 N 4 nanosheets with a single atomic layer structure are prepared by a simple chemical exfoliation method.The as-prepared nanosheets show a single atomic thickness of 0.4 nm and a lateral size of micrometers.The structure and photocatalytic properties of the as-prepared single layer g-C 3 N 4 are then studied.Compared with the bulk g-C 3 N 4 , single layer g-C 3 N 4 nanosheets show great superiority in photogenerated charge carrier transfer and separation. Accordingly, the photocatalytic H 2 production and pollutant decomposition activities and photocurrent generation of single layer g-C 3 N 4 nanosheets are much higher than those of the bulk g-C 3 N 4 , indicating the great application potential of single layer g-C 3 N 4 nanosheets in photocatalysis and photosynthesis.

Surface hybridization of TiO2 with graphite‐like carbon layers of a few molecular layers thickness yields efficient photocatalysts. Photoelectrochemical measurements confirm an electronic interaction between TiO2 and the graphite‐like carbon. A TiO2 photocatalyst with a carbon shell of three molecular layers thickness (∼1 nm) shows the highest photocatalytic activity which is about two times higher than that of Degussa P25 TiO2 under UV light irradiation. The mechanism of the enhanced photocatalytic activity under UV irradiation is based on the high migration efficiency of photoinduced electrons at the graphite‐like carbon/TiO2 interface, which is due to the electronic interaction between both materials. In addition, a high activity under visible light irradiation is observed after graphite‐like carbon hybridization. TiO2's response is extended into the visible range of the solar spectrum due to the electronic coupling of π states of the graphite‐like carbon and conduction band states of TiO2.

No abstract

Driven by applications in chemical sensing, biological imaging and material characterisation, Raman spectroscopies are attracting growing interest from a variety of scientific disciplines. The Raman effect originates from the inelastic scattering of light, and it can directly probe vibration/rotational-vibration states in molecules and materials. Despite numerous advantages over infrared spectroscopy, spontaneous Raman scattering is very weak, and consequently, a variety of enhanced Raman spectroscopic techniques have emerged. These techniques include stimulated Raman scattering and coherent anti-Stokes Raman scattering, as well as surface- and tip-enhanced Raman scattering spectroscopies. The present review provides the reader with an understanding of the fundamental physics that govern the Raman effect and its advantages, limitations and applications. The review also highlights the key experimental considerations for implementing the main experimental Raman spectroscopic techniques. The relevant data analysis methods and some of the most recent advances related to the Raman effect are finally presented. This review constitutes a practical introduction to the science of Raman spectroscopy; it also highlights recent and promising directions of future research developments.

No abstract