A Hybrid Transition Metal Nanocrystals-Embedded Graphitic Carbon Nitride Nanosheets System as Superior Oxygen Electrocatalyst for Rechargeable Zn-Air Batteries
作者：Wen-Jun Niu*, Jin-Zhong He, Ya-Ping Wang, Qiao-Qiao Sun, Wen-Wu Liu, Lu-Yin Zhang, Mao-Cheng Liu, Mi
關鍵字：Transition Metal Nanocrystals, Graphitic Carbon Nitride Nanosheets, Electrocatalyst, Oxygen reduction reaction
論文來源：期刊
具體來源：Nanoscale
發(fā)表時間：2020年
In this study, we, for the first time, demonstrate a general solid-phase pyrolysis method to synthesize the hybrid transition metals nanocrystals-embedded graphitic carbon nitride nanosheets, namely M-CNNs, as highly efficient oxygen electrocatalyst for rechargeable Zn-air batteries (ZABs). The ratios between metallic acetylacetonates and g-C3N4 precursor can be controlled where Fe-CNNs-0.7, Ni-CNNs-0.7 and Co-NNs-0.7 composites have been optimized to exhibit superior ORR/OER bifunctional electrocatalytic activities. Specifically, the Co-CNNs-0.7 exhibited not only a comparable half-wave potential (0.803 V vs. RHE) to that of commercial Pt/C catalyst (0.832 V) with a larger current density for ORR but also a lower overpotential (440 mV) toward OER compared with the commercial IrO2 catalyst (460 mV), revealing impressive application in rechargeable ZABs. As a result, the ZABs using the Co-CNNs-0.7 as cathode exhibited an excellent peak power density of 85.3 mW cm?2 with specific capacity of 675.7 mAh g?1 and remarkable cycling stability of 1000 cycles, outperforming the commercial available Pt/C + IrO2 catalysts. The works highlight the synergy from heterointerfaces in oxygen electrocatalysis, thus providing a promising approach for advanced metal-air cathode materials.