Catalytic activity to lithium-thionylchloride battery of different transitional metal carboxylporphyrins

Abstract

The 5-(4-carboxylatomethoxy)phenyl-10,15,20-triphenyl porphyrin ( H 2 Pp ) and its transition metal complex (MPp, M = Zn 2+, Co 2+, Ni 2+, Cu 2+) were synthesized and characterized by IR, UV-vis, MS and elementary analysis. Electrocatalytic effects associated with the reduction of thionyl chloride in a lithium/thionyl chloride ( Li / SOCl 2) battery containing H 2 Pp and its transition metal complex (MPp, M = Zn 2+, Co 2+, Ni 2+, Cu 2+) are evaluated by the relative energy of the battery and discharge time. The results indicate that the energy of Li / SOCl 2 battery catalyzed by CuPp and ZnPp is 103.7%, 106.3%, respectively, higher than that of Li / SOCl 2 battery in the absence of the porphyrins. The energy of Li / SOCl 2 battery whose electrolyte contains NiPp and CoPp is similar to that of the cell in the absence of these complexes. It shows that the electronic configuration of the central metal ion influences a charge-transfer process during the reduction of thionyl chloride. With the increasing numbers of d electrons of the central metal ion, the catalytic activity of MPps was enhanced. The ZnPp with electronic configuration d10 of central metal ion exhibits relatively high catalytic activity.