Prussian blue analogue derived NiCo alloy nanoparticle encapsulated in N-doped CNT arrays as electrocatalyst for oxygen reduction reaction

초록

, NiCo alloy nanoparticle encapsulated in N-doped CNT (NiCo-NCNT) were fabricated via facile coprecipitation method, followed by high temperature annealing process. First, NiCo-PBA was synthesized using a typical co-precipitation strategy at room temperature. The NiCo-PBA is commonly used as the template for the formation of alloy nanoparticle and growth of carbon nanotubes because of simple synthetic procedure, intrinsic 3D porous structure, and tunable composition of metal species. After that, the prepared NiCo-PBA was annealed with dicyandiamide (DCD) at 750 °C for 90 min in Ar atmosphere to fabricate NiCo-NCNT. During the thermal decomposition of DCD, in-situ generated NH3 gas facilitate the formation of NiCo alloy nanoparticle, simultaneously leading to the catalytic growth of the N doped CNT. The prepared NiCo-NCNT electrocatalyst shows excellent ORR activity with a half-wave potential of 0.827 V vs. RHE, which is comparable with the state-of-the-art Pt/C catalyst. The enhanced electrocatalytic performances for ORR of NiCo-NCNT is mainly attributed to synergistic effect of N-doped CNT with high electric conductivity and uniformly distributed NiCo alloy nanoparticle which can modulate the reaction energy barrier owing to different inherent polarity of the alloy components.