钴和氮修饰的多孔碳作为高效的析氢电催化剂的研究

The Synthesis of Cobalt and Nitrogen Functionalized Carbon as an Efficient Electrocatalysts for HER

采用水热的方法制备了钴修饰的3D石墨烯水凝胶,将该水凝胶浸渍在2-甲基咪唑溶液中获得了ZIF-67与3D石墨烯的复合材料,其结合了3D石墨烯和ZIF-67的孔结构特征,通过改变热解温度对材料的功能性和孔结构进行调节,经过高温热解后制得的金属钴纳米粒子嵌入于N掺杂多孔碳的材料(Co/N/GA)。通过SEM、TEM、XRD、XPS和Raman等测试手段对催化剂进行了形貌和结构的表征,以及利用循环伏安曲线、线性扫描伏安法、交流阻抗谱图和计时电流等谱图对电化学性能进行了详细的研究。结果表明,所制备的钴、氮双掺的多级孔碳材料具有较高的比表面积、较高的氮含量和优异的电子传输能力,因此优化的Co/N/GA-900催化剂在酸性和碱性溶液中,电催化析氢反应起始过电位分别为0和30mV,电流密度在10mA/cm^2的电位分别是45和67mV,Tafel曲线斜率分别为44和88mV dec^(-1),证明了本文所获得的催化剂具有优异的催化活性,而且稳定性测试也说明该催化剂具有优异的稳定性。

Firstly, ZIF-67 and 3D graphene hybrid was constructed by combining solvothermal and dipping method. Then, the hybrid was pyrolyzed to get cobalt and nitrogen co-modified porous carbon electrocatalyst. The chemical composition and porosity structure could be adjusted by controlling the annealing temperature. The electrocatalysts were characterized by XRD, SEM, TEM and Raman technologies. And the electrocatalytic performance was evaluated by CV,LSV,and AC impedance spectra. It was found that the optimized catalyst showed the onset overpotential of 0 and 30mV, required the overpotential of 45 and 67mV to deliver 10mA/cm^2 and gave the Tafel slope of 44 and 88mV dec.1 in acidic and alkaline solution,respectively,confirming the superb activity HER.