采用溶胶-凝胶法制备纳米钙钛矿型复合氧化物催化剂SrTi1-xLixO3-δ(x=0、0.025、0.050)，用微型催化反应评价装置结合XRD、TEM、原位ESR和程序升温表面反应（TPSR）等方法，研究甲烷氧化偶联（OCM）纳米 SrTi1-xLixO3-δ催化剂结构和催化性能。结果表明，B位掺杂适量的低价Li+离子可优化纳米SrTiO3催化剂低温(～650℃ )甲烷氧化偶联催化性能，Li+掺杂量为0.025时获得最高的甲烷转化率和C2选择性。与柠檬酸法制相同组成的常规催化剂相比，SrTi0.975Li0.025O3-δ纳米催化剂具有较优良的低温OCM催化性能和相同温度下更高的C2选择性。SrTi0.975Li0.025O3-δ纳米催化剂优良的催化性能与其表面原子配位不饱和存在F中心相关。
Perovskitetype SrTi1-xLixO3-δ(x = 0, 0.025, 0.050) nano catalyst was prepared by using sol-gel method. Its structure was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), in-situ electron spin resonance (ESR), and temperature-programmed surface reaction (TPRS); its catalytic performance for oxidative coupling of methane (OCM) was measured in a microreactor. The results indicated that the OCM catalytic performance at low temperature (about 650℃) is enhanced by doping Li+ cation to the B site of perovskitetype SrTiO3 nano catalysts; the SrTi1-xLixO3-δ nano catalyst with x = 0.025 performs best. Compare with the conventional catalysts of the same composition prepared by citric acid method, SrTi0.975Li0.025O3-δ nano catalyst performs much better for OCM reaction at low temperature; higher C2 selectivity is achieved at the same temperature. In-situ ESR results showed that there exist O- with ESR signal at g = 2.0430 and F center with ESR signal at g = 2.0080 in the nano SrTi0.975Li0.025O3-δ catalyst, while the conventional SrTi0.975Li0.025O3-δ catalyst shows O2- with the ESR signals at g∥ = 2.014 and g⊥ = 1.9906. The high catalytic performance of SrTi0.975Li0.025O3-δ nano catalyst is related to F centers due to the low coordination surface atoms on the nano oxide particles. F center may activate CH4 at lower temperature and lead to the formation of C2 hydrocarbons with higher selectivity.