Dealloying kinetic and catalytic applications of hierarchical porous copper via hot-dip galvanization and subsequent vapor phase dealloying

Abstract

Hierarchical porous copper (HPC) was synthesized using a Cu-Zn liquid phase alloyed on a Cu tube followed by vapor pressure dealloying. This study demonstrates that HPC with ligament sizes of 0.61–1.97 µm and residual Zn contents of 29–2 at% can be synthesized with a dealloying time of 0.5–30 min and temperature of 773–973 K. The coarsening exponent of 4.099 suggested that the ligament formation and coarsening are attributable to surface diffusion. At the same time, the activation energy of 0.29 eV further confirmed that the Cu atoms diffused on the Cu surface dominated the coarsening of Cu ligaments in this vapor phase dealloying system. The double-layer capacitance of the HPC tube is 34 times higher than that of the electropolished Cu tube. Further, the current density of the CO2 reduction reaction for HPC is two times that of the electropolished Cu tube. With the interaction of Cu and Zn and the use of HPC as an electrocatalyst, the CO2 reduction products transformed from formic acid to carbon monoxide and ethanol.