Phys.org September 13, 2022
The direct electrolysis of seawater is greatly inhibited by the oxidation of Cl– to free chlorine, an undesirable, corrosive byproduct. To suppress the interference of Cl– and any other ion, researchers in Canada developed a freestanding, electrically conducting, 3D macroporous reduced graphene oxide (rGO) scaffold with cobalt oxide particles selectively deposited on the internal walls of its closed pores. The pore walls act as membranes composed of stacked rGO flakes; the nanochannels between rGO layers are permeable to water and gases while preventing the diffusion of dissolved ions such as Cl–. Due to this, the catalytic particles are selectively accessible to water molecules but not to ions, allowing electrolysis to occur without chlorine evolution. The electrodes exhibited a stable generation of O2 from simulated seawater at pH 14, reaching a specific current density of up to 25 A g–1 during continuous electrolysis with 89–98% Faradaic efficiency, while chlorine generation was below 6 ppm h–1, the sensitivity limit of the detection method employed. According to the researchers this strategy can be generalized to build electrodes that are inherently selective with catalytically active particles loaded into closed pores with selective ion transport properties…read more. TECHNICAL ARTICLE
CAPTION: Graphical abstract. Credit: ACS Nano 2022, 16, 8, 12488–12499, August 3, 2022Â