双掺杂石墨烯纳米带气凝胶负载贵金属催化剂的可控合成及其在直接甲醇燃料电池中的应用

Since the problem of energy crisis and environment pollution is becoming more and more severe, direct methanol fuel cells (DMFCs) have gained extensive attention as “green” power generators due to their high energy density and low pollutant emission properties. However, the slow kinetic rate of methanol oxidation as well as the high manufacturing costs of fuel cells largely hamper the commercial progress of DMFCs. To circumvent the above problems, one effective strategy is to develop high-performance electrode catalysts with advanced configuration. The aim of this project is to design and construct dual-doped graphene nanoribbon aerogel-supported noble metal catalysts, and investigate their electrocatalytic properties toward methanol oxidation reactions. The synthesis of the above catalytic systems mainly involves chemical oxidation, solvothermal, thermal annealing, and noble metal loading processes. By adjusting the reaction parameters, the composition, structure and morphology of the products can be effectively controlled. The resulting hybrid catalysts are expected to provide a series of distinctive features, such as 3D cross-linked porous networks, large surface area, high electrical conductivity, uniform heteroatom distribution as well as good metal dispersion, giving them exceptional electrocatalytic activity, outstanding poison tolerance as well as superior long-term stability. On this basis, the project will also delve into the mechanisms for the catalytic enhancement of dual-doped graphene nanoribbon aerogel-supported noble metal catalysts.

由于能源危机与环境污染问题日益严峻，直接甲醇燃料电池作为一种“绿色”的发电装置因其较高的能量密度和较低的污染排放受到了广泛关注。然而，甲醇氧化缓慢的动力学速率以及电池高昂的制造成本在很大程度上阻碍了直接甲醇燃料电池的商业化进程。为了应对上述问题，开发具有先进构造的高性能电极催化剂是一条行之有效的途径。本项目拟设计、构筑双掺杂石墨烯纳米带气凝胶负载贵金属催化剂并研究其对甲醇氧化反应的催化性能。该催化体系的合成主要涉及化学氧化、溶剂热、热处理以及贵金属负载等过程。通过调节反应参数，可对产物的组成、结构及形貌进行有效控制。最终得到的杂化催化剂有望具有三维交互的多孔网络结构、较大的比表面积、良好的导电性、均匀的杂原子分布以及较好的贵金属分散等特性，从而表现出优异的电催化活性、突出的抗中毒能力以及出色的稳定性。在此基础上，项目还将对双掺杂石墨烯纳米带气凝胶负载贵金属催化剂的催化增强机理进行深入探究。

在全球能源危机和环境污染的双重压力下，直接甲醇燃料电池因能量转换效率高且绿色环保而受到了广泛关注，但其大规模商业化应用仍受制于高性能、低成本贵金属催化剂的匮乏。因此，设计高化学活性的载体材料，提高贵金属的利用效率，构筑具有先进纳米结构的新型电极催化剂有着重要的研究价值和意义。近年来，石墨烯因其独特的物理化学性质被认为是一种理想的贵金属载体材料。然而，传统石墨烯缺乏足够的孔道来帮助促进燃料传质和产物分离，且单一的化学结构使其表面呈现出天然的惰性，在很大程度上限制了催化剂的整体性能。有鉴于此，本项目一方面通过自组装技术构建了三维石墨烯气凝胶结构，另一方面采用双重杂原子掺杂来优化石墨烯的电子结构和化学活性，并将多样化的贵金属纳米晶负载在双掺杂石墨烯气凝胶载体表面，从而发展了一系列高性能的直接甲醇燃料电池催化剂材料。在此基础上，项目系统地研究了复合催化剂的三维多孔网络结构、掺杂原子种类及含量、贵金属尺寸及分布等因素对其甲醇氧化催化活性的影响规律，阐明了内在的构-效关系。同时，基于密度泛函理论，项目针对双掺杂石墨烯气凝胶负载贵金属催化剂建立了相关的理论模型，从原子和分子层面揭示了复合体系的微观催化机理。