铂是质子阻断催化剂吗？
Is Platinum a Proton Blocking Catalyst?
AI总结：
本文通过原位电化学石英晶体微天平及原子探针等技术，发现铂在析氢反应中并非仅表面吸附质子，而是存在显著的体相氢/氘扩散，挑战了传统认知，需扩展催化剂设计策略。
摘要：
迄今为止，铂是酸性介质中析氢反应（HER）应用最广泛的电催化剂。人们假定它是一种质子阻断催化剂，反应中间体仅在表面发生限域吸附。在此，我们通过采用电化学石英晶体微天平，在恒电流重水/水分解过程中监测铂电极的原位质量变化，严格评估了铂与氢（H）及其较重同位素氘（D）的体相相互作用。出乎意料的是，我们观察到不可逆的时间性质量增加以及反应过电势的变化，这些源于H/D向铂内部的扩散，并通过原子探针层析术和热脱附谱得到了证实。观察到铂中亚表面D的浓度至少约为15 at.%，扩散深度超过10 nm。解析描述量化了D在铂中的扩散系数为3.2×10^-18 cm²·s⁻¹。这些发现挑战了现有关于铂-质子相互作用仅限于表面的观念，促使催化剂设计策略扩展，以考虑H/D在铂基体中改变性能的体相扩散。
英文摘要：
Platinum, to date, is the most widely applied electrocatalyst for hydrogen evolution reaction (HER) in acidic media. It is assumed to be a proton-blocking catalyst with only surface-limited adsorption of the reaction intermediates. Here, we critically evaluate the bulk interaction of Pt with hydrogen (H), and its heavier isotope deuterium (D), by monitoring operando mass change of the Pt electrode during galvanostatic heavy/water splitting by employing an electrochemical quartz crystal microbalance. Unexpectedly, we observe an irreversible temporal mass gain and a change in the reaction's overpotential, arising from diffusion of H/D into Pt, confirmed by atom probe tomography and thermal desorption spectroscopy. Sub-surface concentration of at least ca. 15 at. % of D in Pt was observed, diffusing down to a depth of more than 10 nm. Analytical description quantified the diffusion coefficient of D in Pt to be 3.2X10^-18 cm2Xs-1. These findings challenge the existing credence of Pt-proton interaction being limited to the surface, prompting the expansion of the catalyst design strategies to account for property-modifying bulk diffusion of H/D in the Pt matrix
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