内核含Pd的Pt基核壳结构电催化剂

燃料电池汽车已被确立为我国的战略性新兴产业,目前正处于大规模商业化的前夜,铂基电催化剂作为质子交换膜燃料电池的核心材料之一,其活性、耐久性和成本制约着这一洁净能源技术的进一步发展。高性能低铂核壳电催化剂被广泛认为有望解决这一瓶颈问题,虽然国内外在这一领域的研究取得了诸多重要的进展,但是仍存在着制备过程复杂、非铂贵金属内核尺寸较大及核壳结构宏观表征困难等问题。本文介绍两种相对简单、易放大的制备方法,即一锅法和液相合成结合区域选择原子层气相沉积法,均获得了性能优良的Pd3Au@Pt/C核壳结构电催化剂,Pd3Au内核尺寸控制在约5 nm,并利用循环伏安测试和甲酸氧化反应从宏观角度研究了铂层在内核表面的覆盖情况,探索了含钯核壳结构电催化剂的新型宏观表征方法。

Pd-Containing Core/Pt-Based Shell Structured Electrocatalysts

Fuel cell vehicles (FCVs) have been a burgeoning industry in China, and are currently on the verge of widespread commercialization. The platinum-based electrocatalyst is one of the key materials in proton exchange membrane fuel cells (PEMFCs). The relatively low activity and durability, and high cost of the electrocatalyst impede the further development of PEMFCs as a clean energy technology. It has been widely anticipated that core-shell structured low-platinum electrocatalysts with high performance toward oxygen reduction reaction (ORR) will eventually resolve this bottleneck issue. Regardless of significant progress, there are still many remaining issues, such as complicated synthesis route, the large sizes of core materials like Pd, and lack of macroscopic characterization of the core-shell structures. Herein, we introduce two new synthetic methods (one pot synthesis and regioselective atomic layer deposition (ALD) combined with a wet chemical method) for the fabrication of core-shell structured Pd₃Au@Pt/C electrocatalysts with high ORR performance. These two synthetic approaches allow us to well control the diameter of the core nanoparticle to around 5 nm. Cyclic voltammetry (CV) and formic acid oxidation reaction (FAOR) were found to be suitable for investigating the integrity of the Pt shell on the core particles. This work represents a new avenue for the macroscopic characterization of the core-shell structured electrocatalysts with Pd or Pd alloy as the core material.