Strain engineering has been utilized as an effective approach to regulate the binding of reaction intermediates and modify catalytic behavior on noble metal nanocatalysts. However, the continuous, precise control of strain for a depiction of strain-activity correlation remains a challenge. Herein, Pd-based nanooctahedrons coated with two Ir overlayers are constructed, and subject to different postsynthetic treatments to alter the amount of H intercalated into Pd core for achieving three different surface strains (o-Pd/Ir-1.2%, o-Pd/Ir-1.7%, and o-Pd/Ir-2.1% NPs). It is demonstrated that the catalytic performances of o-Pd/Ir NPs display a volcano-shaped curve against strains toward the hydrogen evolution reaction (HER). Specifically, o-Pd/Ir-1.7% NPs exhibit superior catalytic performance with a mass activity of 9.38 A mg_Ir⁻¹ at −0.02 V versus reversible hydrogen electrode, 10.8- and 18.8-fold higher than those of commercial Pt/C and Ir/C, respectively, making it one of the most active HER electrocatalysts reported to date. Density function theory calculations verify that the moderate tensile strain on Ir(111) surfaces plays a pivotal role in optimizing the H binding energy. This work highlights a new strategy for precise control over the surface strain of nanocrystals for more efficient electrocatalysis.

中文翻译：

---

精确的应变调节促进电催化制氢

应变工程已被用作调节反应中间体的结合和改变贵金属纳米催化剂的催化行为的有效方法。然而，连续、精确地控制应变以描述应变-活动相关性仍然是一个挑战。在此，构建了涂有两个 Ir 覆盖层的 Pd 基纳米八面体，并进行不同的后合成处理，以改变插入 Pd 核中的 H 量，从而实现三种不同的表面应变（o -Pd/Ir-1.2% 、 o -Pd / Ir-1.7% 和o -Pd/Ir-2.1% 纳米颗粒）。结果表明，o -Pd/Ir NPs 的催化性能对析氢反应 (HER) 的应变表现出火山形曲线。具体而言，o -Pd/Ir-1.7% NPs表现出优异的催化性能，与可逆氢电极相比，在-0.02 V下的质量活性为9.38 A mg _Ir ^-1，比商业Pt/C和Pt/C电极高10.8倍和18.8倍。 Ir/C 分别使其成为迄今为止报道的最活跃的 HER 电催化剂之一。密度函数理论计算验证了 Ir(111) 表面的适度拉伸应变在优化 H 结合能方面发挥着关键作用。这项工作突出了一种精确控制纳米晶体表面应变以实现更有效电催化的新策略。