Yunxiang Chen

Sr(0.4)H(1.2)Nb(2)O(6)·H(2)O nanopolyhedra: an efficient photocatalyst.

A photocatalyst Sr(0.4)H(1.2)Nb(2)O(6)·H(2)O (HSN) nanopolyhedra with high surface area has been successfully prepared by a simple hydrothermal method. The as-prepared samples were characterized by XRD, BET, SEM, TEM and XPS. The electronic structure of HSN determined by DFT calculations and electrochemical measurement revealed that HSN is an indirect-bandgap and n-type semiconductor, respectively. HSN samples showed high photocatalytic activities for both pure water splitting and the decomposition of benzene. The rate of H(2) evolution over HSN was 15 times higher than that of P25 and the conversion ratio of benzene exceeded twice that of P25. The photocatalytic activities for water splitting can be greatly improved by loading various co-catalysts on HSN, such as Au, Pt, and Pd. The photocatalytic mechanisms were proposed based on the band structure and characterization results of the photocatalyst.

Few-layer selenium-doped black phosphorus: synthesis, nonlinear optical properties and ultrafast photonics applications

We reported on the synthesis of high quality bulk selenium (Se)-doped black phosphorus (BP) crystals using a mineralizer assisted gas-phase transformation in a mild growth condition and employed a liquid phase exfoliation approach to obtain few-layer (FL) Se-doped BP nano-sheets from the bulk counterpart. We experimentally found that FL Se-doped BP shows enhanced optical saturable absorption with long term stability, which may originate from selenium doping-induced changes of intrinsic carrier density. Taking advantage of its nonlinear optical property, we designed an optical saturable absorber (SA) device based on FL Se-doped BP, allowing the generation of a femto-second pulse in the fiber laser. Our results not only provide a new strategy in tailoring the nonlinear optical response of BP through element doping, but also suggest that FL Se-doped BP can be developed as a excellent candidate for ultrafast photonics.