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以低价元素掺杂SrTiO_3形成的SrTi_(1-x)MxO_(3-δ)(M=Al~(3+),Mg~(2+),Li~+;x=0～0.2)基本保持了SrTiO_3晶格结构。随着掺杂元素价态的降低和掺杂量的增加,p型电导升高,甲烷氧化偶联反应的C_2选择性和C_2收率也增加。在以不同价态元素掺杂的SrTiO_3体系中,发现C_2选择性和C_2收率与催化剂P型电导间有线性关系。认为掺杂SrTiO_3催化剂中的正导电空穴易与晶格氧发生电子交换生成部分还原态的活泼氧物种O~-,它可以使CH_4分子活化生成CH_3,进一步偶联生成C_2产物。掺杂SrTiO_3催化剂在甲烷氧化偶联反应初始阶段可吸收反应中产生的CO_2,使结构发生少许变化,稳定的SrTiO_3结构有利于甲烷氧化偶联活性的稳定。
SrTi_ (1-x) MxO_ (3-δ) (M = Al ~ (3 +), Mg ~ (2 +), Li ~ +; x = 0 ~ 0.2) doped with SrTiO_3 SrTiO_3 lattice structure. With the valence of the doping element decreased and the doping amount increased, the p-type conductivity increased and the C 2 selectivity and C 2 yield of the methane oxidation coupling reaction also increased. In SrTiO_3 doped with different valence elements, it was found that there was a linear relationship between C_2 selectivity and C_2 yield and P-type conductivity. It is considered that the positively conductive holes in the doped SrTiO_3 catalyst are easy to exchange electronically with the lattice oxygen to form partially reduced active oxygen species O ~ -, which can activate the CH_4 molecule to generate CH_3 and further couple to produce the C_2 product. The doped SrTiO_3 catalyst can absorb the CO_2 produced in the reaction during the initial stage of methane oxidative coupling reaction, resulting in a slight change of structure. The stable SrTiO_3 structure is favorable for the stability of methane oxidative coupling activity.