中文摘要：

采用溶胶-凝胶法制备出SrB2O4和SrCO3复合催化剂（SrB2O4／SrCO3）．紫外光催化还原CO2生成CH·的实验证明，SrB2O4/SrCO3复合催化剂的光催化活性已超过SrB2O4和TiO2（P25）催化剂．利用X射线电子衍射（XRD）谱、透射电子显微镜（TEM）和等温氮气吸附一脱附分析确定了催化剂的晶相结构、粒子尺寸和比表面积．利用紫外．可见（UV-Vis）漫反射吸收光谱、X射线光电子能谱（XPS）的价带谱和荧光光谱（PL）确定了催化剂的能带结构。结果表明：SrB2O4/SrCO3复合催化剂异质结构有利于光生载流子的分离，从而抑制了光生电子和光生空穴的复合，提高了光生电子和光生空穴在固液界面参加光催化反应的利用率．因此，SrB2O4/SrCO3复合催化剂的紫外光催化活性得到了有效的提高．

英文摘要：

An SrB2O4/SrCO3 composite catalyst is synthesized by the simple sol-gel method. Reduction of carbon dioxide into methane in the presence of water is used to evaluate the photocatalytic activity of the composite catalyst.SrB2O4/SrCO3 exhibits better photocatalytic performance than TiO2（P25） and SrB20, under irradiation with UV light. The crystalline structure, crystallite size, and the BET surface areas of the resultant photocatalysts are studied via the techniques of X-ray diffraction （XRD）, transmission electron microscopy （TEM）, and nitrogen adsorption-desorption isotherms. The energy levels of the SrB2O4/SrCO3 photocatalyst are determined from characterization with UV-Vis diffuse reflectance absorption spectra, X-ray photoelectron spectroscopy （XPS）, and photoluminescence （PL） measurements. The heterojunction formed at the SrB2O4/SrCO3 interface efficiently promotes photogenerated carrier separation and increases the use of photogenerated carriers in photocatalytic reactions at the solid/liquid interface, resulting in high photocatalytic activity under UV light.