CoV基电催化剂合成及锌-空电池性能研究

Synthesis of carbon-based CoV electrocatalyst and its application in Zn-air battery devices

贵金属催化剂通常被认为是氧还原反应和氧析出反应缓慢的四电子转移机理的最佳电催化剂。但由于其成本高,资源稀少且稳定性不足,使大规模的商业化受到了限制。因此,在同等催化性能的条件下,低成本且环境友好的非贵金属电催化剂将成为未来电催化剂工程的重点。以二氰二胺为碳源,利用基团配位作用结合冷冻干燥策略,经过碳化处理制备CoV碳纳米管复合材料(命名为CoV-NC)。通过扫描电镜、X-射线衍射光谱、N2吸附—脱附曲线等对样品进行形貌和结构表征。在0.1 M KOH电解液中,CoV-NC催化剂的ORR起始电位为0.931 V,并具有较高的极限电流密度。在电流密度为10 mA·cm^(-2)时,OER电压仅为1.63 V,证明CoV-NC具有较好的ORR和OER催化活性。作为空气—正极材料组装成的一次锌-空电池,在5 mA·cm^(-2)电流密度下可连续放电166 h,性能优于商业Pt/C催化剂。

Precious metal catalysts are generally considered to be the best electrocatalysts for slow four-electron transfer mechanism in oxygen reduction and oxygen evolution reactions.However,its large-scale commercialization is limited due to its high cost,scarce resources and lack of stability.Therefore,under the same catalytic performance conditions,low cost and environmentally friendly non-noble metal electrocatalyst will become the focus of future electrocatalyst engineering.Dicyandiamine was used for carbon resource to prepare CoV-based carbon nanotube composites(named CoV-NC)by means of group coordination combined with freeze drying strategy and carbonization treatment.The morphology and structure of the sample was characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD)and N2 adsorption-desorption curve.In 0.1 M KOH electrolyte,the Eonset potential of CoV-NC catalyst for ORR is 0.931 V,and the limiting current density is higher.The OER voltage is only 1.63 V at the current density of 10 mA·cm^(-2),demonstrating that CoV-NC exhibits good catalytic activity of ORR and OER.As for an air-cathode material to assemble primary Zn-air battery,it can discharge continuously for 166 h at a current density of 5 mA·cm^(-2),which is much better than commercial Pt/C catalyst.