Controlling indoor air borne acetaldehyde is critical in practical way. Instead of common adsorptive removal, a gas phase sustainable removal method at ambient temperature needs to be developed. Here comes electrochemical method for ambient temperature removal under sustainable way. Although liquid phase oxidative acetaldehyde removal is a matured method, a gas phase removal is in infant stage because of hindrance of electron transfer phenomena. To avoid complete mineralization to CO<sub>2</sub> by oxidative removal process, electro-reductive process can be an advantageous to control intermediate compounds that are useful to further needed applications. One obstacle in electro-reductive removal is stabilization of low-valent active mediator for sustainable usage. Here in, authors attempted layered double hydroxide (LDH) cathode as mediator precursor made under high pH condition for the gas phase removal of acetaldehyde by mediated reductive process at cathodic half-cell. A NiAl-LDH selected as precursor that was prepared using hydrothermal method. Different modification methods of NiAl-LDH on NiCrFeAl 3D foam electrode optimized such as in-situ coating during hydrothermal preparation process, cast coating with suitable binder, and electrochemical coating with suitable monomer. The electrochemical coating carried out by electrochemical co-deposition method in presence of pyrrole with NiAl-LDH by constant potential method at 1.2 V with different deposition timings. After the surface characterization of the precursor coating on 3D foam electrode, the LDH electrode served as a cathode in a membrane divided electrochemical cell. Suitable parameters such as current density, gas flow rate, feed concentration of acetaldehyde effect will be tested towards optimization. Also, O<sub>2</sub> or air effect will be tested for the sustainable reductive removal. A semi continuous electro-reductive removal of acetaldehyde will be optimized with online FTIR gas analyzer and offline GC analysis. Based on the GC-MS analysis results, a reductive reaction scheme will be proposed.

Layered double hydroxide coating on 3-dimension foam electrode as a ligand-free solid mediator for electro-reductive removal of gaseous acetaldehyde at solid-gas interphase

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.