Robust and Scalable Synthesis of High Surface Area Porous Copper Spheriodized Powders by Electroless Chemical Dealloying

Abstract In the past decade, nanoporous metals have been a point of interest in the scientific community because they exhibit chemical, optical, and mechanical properties that are unique from their bulk counterparts. One of the most prominent method for its synthesis is chemical dealloying. While, under electrolytic conditions, dealloying can use process-inputs such as current density and electrical potential to control the ligament size during its synthesis with excellent reproducibility, electroless methods are plagued by the lack of local control of dealloying rates which introduces batch-to-batch variations in ligament size. Given that powder is a format incompatible with electrolysis, this study shows an approach to safely scale fabrication of spherical porous copper powders containing oxides from gas atomized Cu-Al powders. Additionally, the agglomeration that is commonly associated with porous powder fabrication was addressed by its functionalization with an anionic surfactant and powder washing in both deionized water (polar) and anhydrous ethanol (nonpolar). Additionally, hazards associated with its production scaling such as excessive hydrogen evolution, heat generation due to its high-reactivity and exothermic reaction and pyrophoricity are discussed and addressed. As a result of this study, a robust and scalable approach was developed to produce 100 of grams of porous metal powders.