电化学脱合金制备纳米多孔Ag及其甲醛检测性能

Nanoporous silver (NPS) with high specific surface area has a great potential application in efficient formaldehyde detection. In this work, NPS was prepared by potentiostatic or galvanostatic electrochemical dealloying of Ag₃₀Zn₇₀ precursor alloys. The results reveal that applied potential or current has a significant influence on the composition, morphology and nanoporous structure of NPS. A bi-continuous NPS with an average pore size of 80 nm was obtained by electrochemical dealloying in 0.1 mol/L HCl solution at a constant current density of 2.5 mA/cm² for 6000 s. The cyclic voltammetry experiment results showed that NPS has a superior formaldehyde catalysis and detection abilities in 0.5 mol/L KOH solution due to the optimal combination of nanopores and Ag ligaments in nanoporous structure. The higher formaldehyde catalysis and detection abilities were exhibited at the NPS with smaller nanopores. The detection sensitivity of formaldehyde in NPS with the pore size of 80 nm was 0.22 mA•cm^-2•(mmol•L^-1)^-1 in the concentration range of 10~100 mmol/L, and the peak current density was 25.0 mA/cm² in 0.5 mol/L KOH solution with 100 mmol/L HCHO.