In situ Construction of Poly-3,4-Ethylenedioxythiophene Skeleton on Carbon Nanotubes to Improve Long-term Stability for Oxygen Reduction Reaction

Although carbon nanomaterials show large potential as efficient electrocatalysts for oxygen reduction reaction(ORR), their inferior long-term stability due to high surface energy result in compact restacking limits their practical performance. To overcome this issue, here, we design and construct an anti-agglormeration single-walled carbon nano-tubes (SWNTs) catalyst by use poly-3,4-Ethylenedioxythiophene (PEDOT) as upholder. Physical characters indicate that PEDOT effectively fill in the interweave zone or adhere to SWNTs surface. Furthermore, S atom can be doped into lattice and produce more defects. Electrochemical tests show that SWNTs@PEDOT has the similar catalytic activities toward ORR to SWNTs, both of them can realize a quasi-4e ORR pathway. Within a 32,000 s long-term practice, cathodic current of SWNTs toward ORR gradually decays to 58 % of the initial value, by contrast, SWNTs@PEDOT shows excellent stability with several stages of rise, fall, rise to 105 % of the initial current. The excellent stability is due to the stable skeleton caused by PEDOT prevent agglomeration of SWNTs. The equilibrium of swelling and shrinkage of PEDOT even lead to an increase and favorable stability of current. This suggests a practical method to overcome the weakness of agglomeration thus enhance the long-term stability for nano carbon catalysts.