"Buried" Surfaces: Membrane-like Coatings for Favorable Electrocatalytic Selectivity

• Published in: Meeting abstracts (Electrochemical Society) Vol. MA2019-01; no. 19; p. 1094
• Main Authors: Mei, Bastian Timo, Endrodi, Balazs, Smulders, Vera, Gomes, Adriano, Widlock, Mats, Simic, Nina, Mul, Guido, Cornell, Ann
• Format: Journal Article
• Language: English
• Published: 01.05.2019
• ISSN: 2151-2043; 2151-2035
• DOI: 10.1149/MA2019-01/19/1094

For existing large-scale industrial processes (chlorate process) as well as emerging technologies (photocatalytic water splitting) electrochemical selectivity towards hydrogen evolution is essential to achieve high (energy) efficiencies. Electrode selectivity is widely reported to be achieved in the presence of solution additives such as sodium dichromate (Na 2 Cr 2 O 7 ) [1]. In the chlorate process dichromate is known to form a thin membrane-like structure by reductive electrochemical deposition on the cathode. With the growing interest in the electrification of the chemical industry and the general need for clean energy technologies, the development of membrane-coated “buried” electrodes recently received increasing attention [2]. In this presentation, 1) the formation of amorphous oxide electrode coatings from chromate solutions will be described and 2) potential alternative coatings, particularly coatings derived from permanganate and vanadate electrolyte additives, will be introduced [3,4]. It will be shown by different electroanalytical techniques that these amorphous oxide overlayers are selectively permeable to certain electroactive species (Figure 1) and enable efficient hydrogen evolution without significantly altered kinetics. References [1] V. Smulders, N. Simic, A.S.O. Gomes, B. Mei, G. Mul, Electrochim. Acta , 2018 , accepted; [2] D.V. Esposito, ACS Catal., 2018 , 8, 457-465; [3] B. Endrődi, V. Smulders, N. Simic, M. Wildlock, G. Mul, B. Mei, A. Cornella, Appl. Catal. B , 2018 , DOI: 10.1016/j.apcatb.2018.11.038; [4] B. Endrődi, S. Sandin, V. Smulders, N. Simic, M. Wildlock, G. Mul, B. Mei, A. Cornell, J. Clean. Prod. 2018 , 182, 529-537.