Monolithic nanoporous (NP) metals have been widely applied in electrochemical catalysis, energy conversion, and energy storage. The interconnected porous metal network provides a large surface area and high conductivity. Dealloying is the most typical method to fabricate NP metals by selectively dissolving one or more components from the master alloy. However, the limited choice of alloys and the complex preparation process of homogenous master alloy precursors always restrict the application. Reduction-induced decomposition (RID) is the selective dissolution of compounds rather than alloys. Unlike dealloying, RID changes precursors from alloys to easily accessible compounds with a wide range of compositions and structures. The facile preparation and flexibility of compounds expand the...[ Read more ]

Monolithic nanoporous (NP) metals have been widely applied in electrochemical catalysis, energy conversion, and energy storage. The interconnected porous metal network provides a large surface area and high conductivity. Dealloying is the most typical method to fabricate NP metals by selectively dissolving one or more components from the master alloy. However, the limited choice of alloys and the complex preparation process of homogenous master alloy precursors always restrict the application. Reduction-induced decomposition (RID) is the selective dissolution of compounds rather than alloys. Unlike dealloying, RID changes precursors from alloys to easily accessible compounds with a wide range of compositions and structures. The facile preparation and flexibility of compounds expand the design possibilities to various NP metals, including NP metal alloys via RID for meeting the diverse needs as efficient electrocatalysts.

In this dissertation, I use RID to fabricate NP metal electrocatalysts. We investigate the effect of the reduction methods, precursor compositions, and alloy product miscibility on the structures of NP metal products. I thereby achieve the fabrication of NP Ag of a controllable thickness and a high population of grain boundaries, NP Ag-Bi of compositional homogeneity at nanoscales, and NP Ni alloys coated on Ni foam, all of which are promising electrocatalysts. I apply the NP Ag to CO₂ reduction to achieve a high selectivity, and use it as a model electrode to confirm the effect of mass transports, supported by finite element analysis. I also apply the NP Ni as a highly conductive cathode in a Zn-air battery. The work demonstrates the great potential of RID as a versatile method for fabricating functional metallic nanostructures.