Jing Liqiang

Review of surface photovoltage spectra of nano- sized semiconductor and its applications in heterogeneous photocatalysis

Abstract Heterogeneous photocatalysis is a promising technique valuable for environmental purification. Nano-sized semiconductors such as ZnO and TiO 2 , which is one of the most basic functional materials, have emerged as effective photocatalyst materials. The surface photovoltage spectra (SPS) can be an effective method for quickly evaluating the photocatalytic activity of semiconductor materials since it can provide a rapid, non-destructive monitor of the semiconductor surface properties such as surface band bending, surface and bulk carrier recombination and surface states, mainly showing the carrier separation and transfer behavior with the aid of light, especially the electric-field-induced surface photovoltage spectra (EFISPS), in which SPS is combined with the electric-field-modified technique. In this review, the basic principles, measurement and applications of the SPS and EFISPS are mainly discussed together with some fundamental aspects like the electric properties of semiconductor surface and the principle of electric field effect. In particular, the applications of SPS to nano-sized semiconductors such as ZnO and TiO 2 in heterogeneous photocatalysis are emphasized, which involve mainly evaluating the photocatalytic activity by analyzing semiconductor surface properties such as the separation efficiency of photoinduced carriers under illumination by the SPS measurement, highlighting our own contributions. The results show that the weaker the surface photovoltage signal is, the higher the photocatalytic activity is in the case of nano-sized semiconductor photocatalysts.

一维Pt/SnO 2 纳米纤维的制备及NO x 气敏性研究

为了制备出室温条件下对NO x 气体具有更高灵敏度和更快响应的传感器纳米材料并研究其气敏性能, 本研究通过高压静电纺丝法制备出一维Pt/SnO 2 中空纳米纤维。采用XRD、SEM、TEM等表征手段对其结构和形貌进行研究, 同时进行了NO x 的气敏性能测试并予以探讨。研究结果表明: Pt/SnO 2 纳米材料是一维中空管状及类似管状结构; 当Pt掺杂量为0.3wt%、NO x 浓度为9.7×10 -5 ( V/V )时, NOx响应最快为11.33 s, 灵敏度最高可达109.6%; 当Pt掺杂量为0.5wt%时, 对NO x 检测限最低浓度可达2.91×10 -6 ( V/V )。为了制备出室温条件下对NO x 气体具有更高灵敏度和更快响应的传感器纳米材料并研究其气敏性能, 本研究通过高压静电纺丝法制备出一维Pt/SnO 2 中空纳米纤维。采用XRD、SEM、TEM等表征手段对其结构和形貌进行研究, 同时进行了NO x 的气敏性能测试并予以探讨。研究结果表明: Pt/SnO 2 纳米材料是一维中空管状及类似管状结构; 当Pt掺杂量为0.3wt%、NO x 浓度为9.7×10 -5 ( V/V )时, NOx响应最快为11.33 s, 灵敏度最高可达109.6%; 当Pt掺杂量为0.5wt%时, 对NO x 检测限最低浓度可达2.91×10 -6 ( V/V )。