【New Journal of Chemistry】Ultrasmall Co2P2O7 Nanocrystals Anchored on Nitrogen-doped Graphene as Efficient Electrocatalysts for Oxygen Reduction Reaction
writer：Kaidi Li, Mingjing Guo, Ya Yan, Ke Zhan, Junhe Yang, Bin Zhao, Jianqiang Li
keywords：Co2P2O7, N-doped graphene, ORR
source：期刊
specific source：New Journal of Chemistry, 2019, DOI: 10.1039/C9NJ00299E.
Issue time：2019年
Although cobalt pyrophosphate (Co2P2O7) has shown promise as potential electrocatalysts for oxygen evolution reaction (OER), its electrocatalytic activity for oxygen reduction reaction (ORR) has rarely been explored. In this work, a novel composite catalyst with in-situ grown Co2P2O7 on nitrogen-doped graphene nanosheets (Co2P2O7/N-rGO) was fabricated by a facile one-step pyrolysis method. Pyrolysis temperature was found to have a significant effect on morphology, structure and ORR performance of the composites. The catalyst fabricated at 800 oC (Co2P2O7/N-rGO-800) presented ultrasmall Co2P2O7 nanocrystals (below 5 nm) anchored on N-rGO and the highest pyridinic-N proportion. Benefiting from full exposure of active sites on the ultrasmall Co2P2O7 nanocrystals, abundant pyridinic-N species and synergistic effect of the Co2P2O7 and N-doped graphene, the optimized Co2P2O7/N-rGO-800 not only demonstrates excellent ORR catalytic activity with a positive cathodic peak potential (0.823 V vs 0.833 V of commercial Pt/C catalyst), but also shows superior durability and methanol crossover resistance to Pt/C in alkaline solution. In addition, the composite catalyst also exhibits reasonable oxygen evolution reaction (OER) performance and impressive OER stability in KOH solution. These findings suggest that the Co2P2O7/N-rGO catalysts may be promising candidates as oxygen electrocatalysts for future energy conversion applications.