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

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 mu m 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. (c) 2022 Elsevier B.V. All rights reserved.

Automated summary

Hierarchical porous copper (HPC) was synthesized by Cu-Zn liquid phase alloying on a Cu tube followed by vapor pressure dealloying. The HPC exhibited ligament sizes of 0.61-1.97 μm and residual Zn contents of 29-2 at%. The coarsening exponent and activation energy suggested that the ligament formation and coarsening were dominated by surface diffusion of Cu atoms on the Cu surface. The HPC showed significantly enhanced double-layer capacitance and current density for CO2 reduction compared to electropolished Cu. The CO2 reduction products transformed from formic acid to carbon monoxide and ethanol. (c) 2022 Elsevier B.V. All rights reserved.