Depletion plating, also known as depletion gilding, has been practiced since ancient civilizations to alter the appearance of metallic objects by depleting Cu near the surface of Au-Cu and Ag-Cu items through selective etching, making them look like pure Au and pure Ag (Sterling Ag), respectively. In modern times, selective etching is widely used to create nanoporous metals, some of which are integral to industries like Raney Ni catalysis. Until now, however, a significant drawback of selective etching is that the removed sacrificial metals, often accounting for over 50 % of the parent material, are waste products. In this article, we demonstrate a versatile electrochemical method for making nanoporous metals that nearly eliminates the loss of sacrificial materials. This method, referred to as chlorine-neutral etching, uses Cl to introduce nanoporosity in metals through the Kirkendall effect, with nearly full recovery of Cl. Etching without losing sacrificial materials will enable a circular economy. Here, we demonstrate this new concept by fabricating a tri-layer nanoporous Ag | Ag | Ag.

中文翻译：

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三层纳米多孔银 |银 |通过 Kirkendall 效果蚀刻而不牺牲材料实现银


自古代文明以来，人们一直在采用贫化镀金，通过选择性蚀刻耗尽 Au-Cu 和 Ag-Cu 物品表面附近的 Cu 来改变金属物体的外观，使它们分别看起来像纯 Au 和纯 Ag （Sterling Ag）。在现代，选择性蚀刻被广泛用于制造纳米多孔金属，其中一些金属是 Raney Ni 催化等行业不可或缺的一部分。然而，到目前为止，选择性蚀刻的一个显着缺点是去除的牺牲金属（通常占母材的 50% 以上）是废品。在本文中，我们展示了一种用于制造纳米多孔金属的多功能电化学方法，该方法几乎消除了牺牲材料的损失。这种方法被称为氯中性蚀刻，使用 Cl 通过 Kirkendall 效应在金属中引入纳米孔隙率，几乎完全回收 Cl。在不损失牺牲材料的情况下蚀刻将实现循环经济。在这里，我们通过制造三层纳米多孔 Ag |银 |银。