金属碳化物基低铂介孔催化材料的合成、界面设计与电催化性能研究

Platinum (Pt) is a common catalyst in many catalytic reactions associated with energy conversion and utilization, such as fuel cells. However, the high cost and scarcity of Pt, and their insufficient stability limit large-scale implementation of Pt catalysts. To overcome these issues, this project proposes the construction of low- and non-Pt catalysts based on mesoporous transition metal carbides (TMCs). Conceptually, active metal nanoparticles are highly stabilized by mesoporous TMCs to form novel nano-hybrids with intimate interface contact. The key innovative elements for the project include the synthesis of mesoporous TMCs with high surface areas to maximize the catalytic activity of TMCs themselves and stabilize active metal components, and the construction of intimate metal@TMCs (M@TMCs) nano-hybrids to optimize their catalytic synergistic effects and stability. To realize the catalyst configuration, this project proposes the utilization and exploration of templating methods to synthesize a series of mesoporous TMCs, including self-supported mesoporous TMCs and mesoporous carbon supported TMC nanoparticles. With the manipulation of experimental parameters, the interfacial structure and chemical composition of the TMCs will be adjusted. Then, through in-situ and post loading methods, active metal nanoparticles will be loaded onto the interface of the mesoporous TMCs with direct contact between metal and TMCs to form intimate nano-hybrids. Finally, their catalytic performance in oxygen reduction reaction, along with the structure-performance relationship, will be studied. The success of this project will not only provides novel approaches on the synthesis of TMCs with high surface areas and tailored nanostructures, but also provides a cost-effective low-Pt or even non-Pt platform for various catalytic applications associated with energy conversion.

铂催化剂在燃料电池等能源装置中发挥重要作用，但其资源有限、成本昂贵；稳定性难以满足需求。为改善这一局面，本项目提出以过渡金属碳化物（TMCs）为基础，构建金属@金属碳化物（M@TMCs）纳米结构，开发高效低铂、无铂催化材料。其核心是：合成高比表面积的金属碳化物材料，以提高其自身的催化活性，并分散后续引入的活性金属；构建金属与金属碳化物直接接触的亲密界面纳米复合材料（intimate nano-hybrids），以优化二者的催化协同效应及稳定性。为实现上述目的，项目拟采取模板法，合成高比表面积的金属（钨、钼等）碳化物介孔材料；进一步调变实验参数，调节金属碳化物的界面化学性质；然后采取原位与后负载的方法引入活性金属组分（铂、钯、钴等），构建界面亲密接触（intimately contacted）的金属@金属碳化物纳米结构材料；最后研究它们在氧气还原等催化反应中的性能与构效关系。

贵金属铂催化材料广泛用于燃料电池、水裂解与精细化工等领域，但其资源有限、成本昂贵，且容易中毒导致催化稳定性不足。针对这些问题，本研究提出了制备高效低铂、无铂介孔催化材料的新思路，围绕金属碳化物与金属-氮-碳介孔催化材料的合成、界面调控与电催化应用开展了较为系统的工作。本研究采用模板合成方法，开发了化学气相沉积、原位转化与纳米限域组装等路线，制备了数种结构新颖、物化性质优良的无铂介孔催化材料，主要包括介孔碳化钼@石墨化碳（Mo2C@GC）核壳纳米线阵列、氮或金属碳化物纳米团簇掺杂的介孔碳以及介孔金属-氮-碳材料，研究了这些材料在制备过程中的结构演变过程，探索了其结构与物化性质的调变规律；在上述基础上，采用后负载法，利用金属与金属碳化物的强相互作用，在金属碳化物表面负载低含量、高分散的贵金属，构筑了具有亲密界面的金属@金属碳化物纳米结构材料（特别是Pt@ Mo2C）；进一步研究了上述所得低铂、无铂介孔催化材料在电催化氧气还原反应（ORR）与析氢反应（HER）中的性能，探索了材料的结构与催化性能的内在联系，获得了数种性能优异的ORR与HER电催化材料；此外，本研究拓展了所得催化材料在其他异相催化中的应用，所得金属-氮-碳介孔材料在硝基化合物选择性加氢反应中具有优异的催化性能。本研究可为高性能非贵金属催化材料的研发提供一定的实验基础与理论支撑，提出的制备方法可为多孔催化材料的研发提供思路，制备的材料可拓展到其他重要的异相催化应用。