Tailoring the Oxygen Reduction Activity of Pt Nanoparticles through Surface Defects: A Simple Top-Down Approach
Tailoring the Oxygen Reduction Activity of Pt Nanoparticles through Surface Defects: A Simple Top-Down Approach
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DOI：
10.1021/acscatal.9b04974
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发表时间：
2020-03-06
期刊：
影响因子：
12.9
通讯作者：
Bandarenka, Aliaksandr S.
中科院分区：
文献类型：
--
作者：
Fichtner, Johannes;Watzele, Sebastian;Bandarenka, Aliaksandr S.
铂模型催化剂表面的结果表明，表面缺陷，特别是表面凹陷，可以改善氧还原反应(ORR)动力学。然而，合成具有这种缺陷表面的纳米结构催化剂是一项具有挑战性的任务。因此，我们提出了一种一步可升级的自上而下的方法来制备铂/碳催化剂(其纳米铂颗粒直径类似于3 nm)。使用高分辨率电子显微镜和断层扫描、电化学技术、高能X射线测量和正电子湮没光谱，我们提供了高密度表面缺陷(包括表面凹陷)的证据。该催化剂的ORR活性在比活性(与可逆氢电极在0.9V时相当于1.62 mA/cm(铂)(2))和质量活性(与712 mA/mg(铂)相当)方面至少是商品铂/碳催化剂的2.7倍，这可能与表面缺陷的增加有关。此外，与最先进的自下而上技术相比，这里使用的技术降低了合成的复杂性(因此降低了生产成本)。
Results from Pt model catalyst surfaces have demonstrated that surface defects, in particular surface concavities, can improve the oxygen reduction reaction (ORR) kinetics. It is, however, a challenging task to synthesize nanostructured catalysts with such defective surfaces. Hence, we present a one-step and upscalable top-down approach to produce a Pt/C catalyst (with similar to 3 nm Pt nanoparticle diameter). Using high-resolution transmission electron microscopy and tomography, electrochemical techniques, high-energy X-ray measurements, and positron annihilation spectroscopy, we provide evidence of a high density of surface defects (including surface concavities). The ORR activity of the developed catalyst exceeds that of a commercial Pt/C catalyst, at least 2.7 times in terms of specific activity (similar to 1.62 mA/cm(Pt)(2), at 0.9 V vs the reversible hydrogen electrode) and at least 1.7 times in terms of mass activity (similar to 712 mA/mg(Pt)), which can be correlated to the enhanced amount of surface defects. In addition, the technique used here reduces the complexity of the synthesis (and therefore production costs) in comparison to state of the art bottom-up techniques.