摘要
采用溶胶-凝胶法制备出偏硼酸锶(SrB_2O_4)光催化剂.紫外光催化还原CO_2合成CH_4(在液相水中)的实验证明:SrB_2O_4催化剂的光催化活性略高于TiO_2(P25).利用X射线电子衍射谱(XRD)、傅里叶变换红外(FTIR)光谱、X射线光电子能潜(XPS)、透射电子显微镜(TEM)、荧光(PL)光谱和紫外-可见(UV-Vis)漫反射吸收光谱等技术,研究了SrB_2O_4催化剂的晶体结构、形貌和能带结构.结果表明:SrB_2O_4的价带为2.07 V(vs normalhydrogen electrode(NHE)),低于(H_2O/H^+)的氧化还原电位E°_(redox)(0.82 V(vs NHE));而导带为-1.47 V(vsNHE),高于(CO_2/CH_4)的氧化还原电化E°_(redox)(-0.24 V(vs NHE)).因此,SrB_2O_4催化剂可以有效地光催化还原CO_2生成CH_4.与TiO_2(P25)相比,SrB_2O_4催化剂具有相对较高导带,光生电子的还原能力强于TiO_2(P25),更有利于CH_4的生成,从而决定了SrB_2O_4催化剂光催化还原CO_2合成CH_4具有较高的光催化活性.
The reduction of carbon dioxide to methane in the presence of water was used to evaluate the photocatalytic activity of a prepared strontium metaborate （SrB2O4） catalyst. The strontium rnetaborate was prepared by a simple sol-gel method, and was shown to exhibit better photocatalytic performance than TiO2 （P25） under UV-light irradiation. The structure, morphology, and energy levels of the photocatalysts were studied by X-ray diffraction （XRD）, Fourier transform infrared （FTIR） spectroscopy, X-ray photoelectron spectroscopy （XPS）, transmission electron microscopy （TEM）, photoluminescence （PL） spectroscopy, and UV-Vis diffuse reflectance absorption spectroscopy. It was revealed that the SrB2O, valence band （VB） was located at 2.07 V （vs normal hydrogen electrode, NHE）, which is more positive than Eredox° （H2O/H＋） （0.82 V （vs NHE））; the conduction band was estimated to be -1.47 V （vs NHE））, which is more negative than Eredox° （CO2/CH4） （-0.24 V （vs NHE））. Therefore, it is clear that strontium metaborate is capable of transforming CO2 into CH,. Moreover, the potential at the bottom of the conduction band for SrB2O, is more negative than that for TiO2（P25）, leading to a higher deoxidization capacity, which also favors CH, formation. Thus. SrB2O, exhibits a higher photocatalytic activity than TiO2（P25）.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2013年第2期397-402,共6页
Acta Physico-Chimica Sinica
基金
国家自然科学基金(51072082
21173121)资助项目~~
