Electrocatalytic activities of REMn_2O_5 (RE = Dy, Ho, Er, Tm, Yb, and Lu) and Er_(0.76)Zr_(0.11)Ca_(0.13)Mn_2O_5 for oxygen reduction in alkaline solution

摘要

A series of complex oxides REMn_2O_5 (RE = Dy, Ho, Er, Tm, Yb, and Lu) and Er_(0.76)Zr_(0.11)Ca_(0.13)Mn_2O_5 with large specific areas and nanoscale grain sizes were prepared by an improved amorphous citric precursor method (IACP). Their electrocatalytic performances were characterized by the polarization curves of gas diffusion electrodes employing the oxides. The measurement of polarization curves indicated that the REMn_2O_5 containing different rare earth showed a obviously different electrocatalytic performances for oxygen reduction reaction, being the order Tm > Er > Ho > Dy > Lu > Yb. Temperature-programmed reduction (TPR) analysis revealed that the REMn_2O_5 containing different rare earth showed a significantly different oxygen contents and TPR peak temperatures. Their catalytic activities depended on both the oxygen contents and TPR peak temperatures. These two factors play a plus and a minus role respectively.