Oxide supports can modify and stabilize platinum nanoparticles (NPs) in electrocatalytic materials. We studied related phenomena on model systems consisting of Pt NPs on atomically defined Co₃O₄(111) thin films. Chemical states and dissolution behavior of model catalysts were investigated as a function of the particle size and the electrochemical potential by ex situ emersion synchrotron radiation photoelectron spectroscopy and by online inductively coupled plasma mass spectrometry. Electronic metal–support interaction (EMSI) yields partially oxidized Pt^δ+ species at the metal/support interface of metallic nanometer-sized Pt NPs. In contrast, subnanometer particles form Pt^δ+ aggregates that are exclusively accompanied by subsurface Pt⁴⁺ species. Dissolution of Co^x+ ions is strongly coupled to the presence of Pt^δ+ and the reduction of subsurface Pt⁴⁺ species. Our findings suggest that EMSI directly affects the integrity of oxide-based electrocatalysts and may be employed to stabilize Pt NPs against sintering and dissolution.

中文翻译：

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氧化钴负载的Pt电催化剂：粒度，电子金属-载体相互作用和稳定性之间的密切相关。

氧化物载体可以修饰和稳定电催化材料中的铂纳米颗粒（NPs）。我们研究了在原子定义的Co ₃ O ₄（111）薄膜上由Pt NP组成的模型系统上的相关现象。通过异位发生同步加速器辐射光电子能谱和在线感应耦合等离子体质谱法研究了模型催化剂的化学状态和溶解行为与粒径和电化学势的关系。电子金属-载体相互作用（EMSI）在金属纳米级Pt NP的金属/载体界面处产生部分氧化的Ptδ ⁺物种。相反，亚纳米粒子形成Ptδ ⁺仅由地下Pt ⁴⁺物种伴生的聚集体。的Co溶出^{X +}离子强烈耦合的Pt的存在^δ+和地下Pt组成的还原⁴⁺物种。我们的发现表明，EMSI直接影响基于氧化物的电催化剂的完整性，并且可用于稳定Pt NP防止烧结和溶解。