基于金属沸石咪唑酯骨架的含氮碳材料的催化氧还原性能

M-ZIF_S derived N-containing carbon material for oxygen reduction reaction

以乙酸钴(锌)、苯并咪唑为原料,采用液相法快速地合成金属沸石咪唑酯骨架(M-ZIFs)材料,通过高温裂解,得到含氮碳材料M-N_x/C,并对其氧还原性能进行研究。通过X射线衍射(XRD),扫描电镜(SEM),透射电镜(TEM),X射线光电子能谱分析(XPS)和电化学测试等手段对合成催化剂的形貌、成分和电催化性能进行了表征。通过比较发现,具有较高的石墨化程度和Co-N_x活性位点的Co-N_x/C材料的催化氧还原性能远高于Zn-N_x/C的,具有较正的氧还原起始电位(0.92 V)和半波电位(0.83 V),接近铂碳的指标;而在稳定性方面,该材料在反应10000s后仍能保持94.2%的电流密度,远高于铂碳的80.8%。

M-Nx/C was obtained by pyrolyzing the M-ZIFs through quick liquid phase reaction of cobalt （zinc） acetate and organic ligand （Benzimidazole）. Then the morphology, composition and electxocatalytic activity were characterized by X-ray diffractometry （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, X-ray photoelectron spectra （XPS） and electrochemical measurements. Compared with Zn-N/C, Co-N/C has higher eletrocatalytic activity for possessing high graphitization and CoNx active sites for oxygen reduction reaction （ORR）. The onset potential and half wave potential of oxygen reduction on Co-N/C electrode are 0.92 V and 0.83 V, respectively, which are close to those of Pt/C. As for the stability, the Co-N/C maintains 94.2% current density after 10000 s, while the Pt/C maintains 80.8%.