WO_3对碳载EMD催化氧还原活性的影响

Effect of WO_3 to catalytic activity of carbon supported EMD for oxygen reduction

研究了助催化剂三氧化钨(WO3)对电解二氧化锰(EMD)催化性能的影响。通过球磨制备5种WO3含量的EMD复合催化剂,进行XRD、SEM和电化学性能测试。WO3影响了EMD的孔隙率,添加适量的WO3可改善EMD的催化性能。添加WO3催化剂的氧还原电位较未添加WO3催化剂提前0.02 V。当电压为-0.15 V时,EMD、(MnO2)33(WO3)0.7、(MnO2)33(WO3)1、(MnO2)33(WO3)1.3及(MnO2)33(WO3)1.5的氧还原电流分别为:-0.21 mA、-0.35 mA、-0.85 mA、-0.53 mA和-0.08 mA,表明随着WO3添加量的增加,EMD的催化性能先提高,后下降。EMD、(MnO2)33(WO3)0.7、(MnO2)33(WO3)1、(MnO2)33(WO3)1.3及(MnO2)33(WO3)1.5制备的电池,放电平台分别为1.05 V、1.08 V、1.21 V、1.14 V和0.98 V;催化活性顺序为:(MnO2)33(WO3)1>(MnO2)33(WO3)1.3>(MnO2)33(WO3)0.7>EMD>(MnO2)33(WO3)1.5。

Effect of tungsten trioxide（WO3） additive to the electrolytic manganese dioxide （EMD） catalyze oxygen reduction ac- tivity was studied. EMD composite catalysts with 5 kinds of WO3 content were prepared by ball-milling. XRD, SEM and linear vol- tage scanning and galvanostatie discharge tests were taken. Adding proper WO3 could improve the catalytic activity of EMD, the porosity of EMD was affected by WO3. Compared with the catalyst without adding WO3, the oxygen reduction potential of catalyst added WO3 was 0.02 V in advance. When the voltage was - 0.15 V, oxygen reduction current of EMD, （ MnO2）33 （ W03 ）0.7, （MnO2）33（WO3）t,（MnO2）33（W03）1.3 and （MnO2）33（WO3）1.5 was - 0.21 mA, - 0.35 mA, - 0.85 mA, -0.53 mA and - 0.08 mA, respectively,indicated that with the increasing of W03 adding amount, the oxygen reduction current increased firstly, then decreased. The discharge platform of cell prepared with EM D, （ MnO2） 33 （WO3） 0.7, （ MnO2 ）33 （ WO3）1, （MnO2） 33 （ WO3 ）1.3 and （MnO2）33（WO3）1.5 was 1.05 V, 1.08 V, 1.21 V, 1.14 V and 0.98 V, respectively. The catalytic activity was in the fol- lowing order：（MnO2）33（WO3）l〉 （MnO2）33（WO3）1.3〉 （MnO2）33（WO3）0.7〉 EMD 〉 （MnO2）33（WO3）1.5.