偏硼酸锶催化剂光催化还原CO2合成CH4

采用溶胶-凝胶法制备出偏硼酸锶(SrB₂O₄)光催化剂. 紫外光催化还原CO₂合成CH₄(在液相水中)的实验证明: SrB₂O₄催化剂的光催化活性略高于TiO₂(P25). 利用X射线电子衍射谱(XRD)、傅里叶变换红外(FTIR)光谱、X射线光电子能谱(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SrB₂O₄ 催化剂的晶体结构、形貌和能带结构. 结果表明: SrB₂O₄ 的价带为2.07 V (vs normalhydrogen electrode (NHE)), 低于(H₂O/H⁺)的氧化还原电位E_redox^o (0.82 V (vs NHE)); 而导带为-1.47 V (vsNHE), 高于(CO₂/CH₄)的氧化还原电位E_redox^o (-0.24 V (vs NHE)). 因此, SrB₂O₄催化剂可以有效地光催化还原CO₂生成CH₄. 与TiO₂(P25)相比, SrB₂O₄催化剂具有相对较高导带, 光生电子的还原能力强于TiO₂(P25), 更有利于CH₄的生成, 从而决定了SrB₂O₄催化剂光催化还原CO₂合成CH₄具有较高的光催化活性.

Photocatalytic Reduction of CO2 into CH4 Using SrB2O4 Catalyst

The reduction of carbon dioxide to methane in the presence of water was used to evaluate the photocatalytic activity of a prepared strontium metaborate catalyst. The strontium metaborate (SrB₂O₄) 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 SrB₂O₄ valence band (VB) was located at 2.07 V (vs normal hydrogen electrode, NHE), which is more positive than E_redox^o (H₂O/H⁺) (0.82 V (vs NHE)); the conduction band was estimated to be -1.47 V (vs NHE)), which is more negative than E_redox^o (CO₂/CH₄) (-0.24 V (vs NHE)). Therefore, it is clear that strontium metaborate is capable of transforming CO₂ into CH₄. Moreover, the potential at the bottom of the conduction band for SrB₂O₄ is more negative than that for TiO₂(P25), leading to a higher deoxidization capacity, which also favors CH₄ formation. Thus, SrB₂O₄ exhibits a higher photocatalytic activity than TiO₂(P25).