Microbial desalination cells with efficient platinum-group-metal-free cathode catalysts

Talarposhti, Morteza Rezaei; Kodali, Mounika; Gokhale, Rohan; Serov, Alexey; Merino-Jimenez, Irene; Ieropoulos, Ioannis; Atanassov, Plamen; Santoro, Carlo

Abstract

© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim. An iron-nitrogen-carbon-based catalyst was used at the cathode of a microbial desalination cell (MDC) and compared with platinum (Pt) and an activated carbon (AC) cathode. The Fe-N−C catalyst was prepared by using nicarbazin (NCB) as the organic precursor through a sacrificial support method (SSM). Rotating ring disk electrode (RRDE) experiments show that Fe-NCB had a higher electrocatalytic activity compared to AC and Pt. The utilization of Fe-NCB in the cathode substantially improved the performance output with an initial maximum power density of 49±2 μW cm−2 in contrast to Pt and AC catalysts, which show lower values of 34±1 and 23.5±1.5 μW cm−2, respectively. After four cycles, Fe-NCB catalyst lost 15 % of its initial performance, but still was 1.3 and 1.8 times more active than Pt and AC, respectively. Solution conductivity inside the desalination chamber (DC) decreased by 46–55 % with every cycle. The pH of the cathodic chamber and the DC increased to 10–11, owing to the production of OH− during the oxygen reduction reaction and the migration of OH− into the DC. Chemical organic demand decreased by 73–83 % during each cycle. It was shown that Fe-NCB and Pt had a similar coulombic efficiency (CE) of 39±7 % and 38±2 %, whereas AC had lower CE (24±5 %).

• Journal Article Type: Article
• Acceptance Date: Aug 21, 2017
• Publication Date: Dec 1, 2017
• Deposit Date: May 4, 2018
• Journal: ChemElectroChem
• Electronic ISSN: 2196-0216
• Publisher: Wiley
• Peer Reviewed: Peer Reviewed
• Volume: 4
• Issue: 12
• Pages: 3322-3330
• DOI: https://doi.org/10.1002/celc.201700626
• Keywords: iron-nitrogen-carbon-based catalyst, microbial desalination cell (MDC), nicarbazin (NCB), sacrificial support method (SSM), rotating ring disk electrode (RRDE)
• Public URL: https://uwe-repository.worktribe.com/output/882866
• Publisher URL: http://dx.doi.org/10.1002/celc.201700626
• Contract Date: May 4, 2018