α-MnO_(2)/MWCNTs复合材料的制备及其电催化氧还原性能研究

Preparation and Electrocatalytic Oxygen Reduction Properties ofα-MnO_(2)/MWCNTs Composites

欠佳的氧还原活性和较差的电子传输能力严重限制了MnO_(2)材料在电催化氧还原反应(ORR)领域中的应用。以多壁碳纳米管(MWCNTs)作为导电载体,采用简单、绿色的两步法成功制备了一种α-MnO_(2)/MWCNTs复合材料,该复合材料展现出了较好的ORR电催化活性,其半波电位和极限电流密度分别达到0.72 V和-5.20 mA·cm^(-2),以4电子转移为主,同时该复合材料还展现出比商业Pt/C催化剂更好的长期稳定性,这主要归因于高导电性MWCNTs的引入以及α-MnO_(2)/MWCNTs独特的三维交织网络结构,为氧化锰基ORR电催化剂的设计提供了一种简便、价廉易得的合成策略,对非贵金属材料在电化学能量转换和存储装置大规模商业化中的应用起到推动作用。

The suboptimal oxygen reduction activity and poor electron transport ability significantly impede the practical application of MnO_(2)in the field of electrocatalytic ORR.In this paper,theα-MnO_(2)/MWCNTs composite was successfully synthesized via a facile and environmentally friendly two-step method,employing MWCNTs as an excellent conductive carrier.Theα-MnO_(2)/MWCNTs exhibited superior electrocatalytic activity towards ORR.The half-wave potential and limiting current density ofα-MnO_(2)/MWCNTs were observed to attain 0.72 V and-5.20 mA·cm^(-2),with 4-electron transfer as the main factor.Meanwhile,the composite also exhibits better long-term stability compared to commercial Pt/C catalysts.The significant improvement can be attributed to the incorporation of highly conductive MWCNTs and the unique three-dimensional interwoven network structure formed byα-MnO_(2)/MWCNTs.This study presents a simple,cost-effective and readily accessible synthetic approach for the development of manganese oxide-based ORR electrocatalysts,thereby facilitating the utilization of non-precious metal materials in large-scale commercialization of electrochemical energy conversion and storage devices.