No abstract

Electrochemical application has been considered a promising technology in environmental remediation. However, the development of hydrocarbon ligand-free mediators for long-term operation still deserves further assessments. In this study, three different combinations (NiAl, CoAl, NiCo) of layered double hydroxide (LDH) electrodes were prepared using in-situ and ex-situ methods. These LDH electrodes were applied as solid electrocatalysts for gaseous acetaldehyde degradation using a membrane-divided flow-through electrolytic cell. In cyclic voltammetry analysis, the in-situ prepared LDH-electrodes had high peak currents in high-valent redox couples (Ni3+/2+Al3+, Co3+/2+Al3+, and Ni3+/2+Co3+/2+) compared to low-valent redox couples (Ni2+/1+Al3+, Co2+/1+Al3+, and Ni2+/1+Co2+/1+). Due to the higher active surface area, the overall redox peak current was higher in the in-situ prepared LDH electrode than the ex-situ LDH electrode. During electrocatalytic degradation of acetaldehyde, the LDH electrodes containing cobalt ions had a higher mediated catalysis activity than the LDH containing nickel ions (NiAl-LDH). The Co3+ ions placed in the layered hydroxide synergistically mediate the electrons to degrade acetaldehyde at the solid-gas interface sustainably.