摘要
用ESR方法研究了CoO-MgO固溶体作为多相氧载体的可逆吸氧性质。发现CoO-MgO表面的Co^(2+)可以以两种方式与分子氧可逆结合,一种形成Co^(2+)-O_2,它给出了与MgO晶格中Co^(2+)相似的各向同性的信号(g=4.2);一种形成Co^(2+)-O_2^-,它给出轴对称的信号(g_‖=2.141,A_‖=30G,g_⊥_=1.980,A_⊥=15G)。我们认为Co^(2+)-O_2是表面Co_(5c)^(2+)与O_2结合产生的,而Co^(3+)-O_2^-是由表面Co_(4c)^(2+)或Co_(3c)^(2+)与O_2结合形成的。
CoO-MgO solid solution as a kind of heterogeneous oxygen carrier was studied by ESR. It was observed that Co2+ on the surface of CoO-MgO could combine with oxygen rev ersibly in two different forms .one was Co2+-O2 with isotropical ESR signal (g=4.2) analogous to the signal of Co2+ on the bulk lattice of MgO, the other was Co8 + -O2- with an axial ESR signal (g|| = 2.141, A||= 30G ,g⊥=1.980, A⊥=15G). It is proposed that Co2+-O2 comes from Co5c2+,and Co3+-O2- comes from Co4c2+ or Co3c2+.
基金
国家自然科学基金
