Bifunctional Mesoporous MOx (M = Cr, Fe, Co, Ni, Ce) Oxygen Electrocatalysts for Platinum Group Metal‐Free Oxygen Pumps. Issue 12 (2nd October 2022)

• Record Type: Journal Article
• Authors: Wu, Zhixing; Vagin, Mikhail; Boyd, Robert; Greczynski, Grzegorz; Ding, Penghui; Odén, Magnus; Björk, Emma M.
• Is Part Of: Energy technology. Volume 10:Issue 12(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-10-02
• Subjects: mesoporous metal oxides -- oxygen evolution reaction -- oxygen pumps -- oxygen reduction reaction -- soft-templating; Energy development -- Periodicals; Power resources -- Periodicals; 333.79
• DOI: 10.1002/ente.202200927
• Languages: English
• ISSNs: 2194-4288

Abstract

Abstract : Bifunctional electrocatalysts with both accelerated oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) enable high‐power density electricity storage and decentralized extraction of pure oxygen from air for usage in health care. Herein, a hydrothermal synthesis employing the anionic surfactant sodium dodecyl sulfate as structure‐directing agent is developed to fabricate a family of crystalline mesoporous metal oxides (meso‐MO X, M = Cr, Fe, Co, Ni, Ce). The pore size and specific surface area depend on the metal used and they range from 3 to 6 nm and 60 to 200 m 2 g −1, respectively. NiO and Co3 O4 show a higher catalytic efficiency in alkaline media in comparison with the other oxides studied, and their activities are comparable with the values reported for platinum group metal (PGM)‐based electrocatalysts. This stems from lower voltage losses and by the presence of specific hydroxide adsorbates on the surface. Both ORR and OER driven on Co3 O4 show the unified rate‐determining chemical step (|OO − | ads + H2 O ↔ |OOH| ads + OH −, where | X | ads are the species adsorbed on active sites). The bifunctional ORR/OER electrocatalysis obtained on mesoporous NiO is utilized for the first symmetrical PGM‐free oxygen pump fed by air and water only. Abstract : The family of high‐quality crystalline mesoporous MO x synthesized via soft‐templated hydrothermal synthesis is investigated in oxygen reduction reaction and oxygen evolution reaction electrocatalysis. Using developed NiO, the symmetrical platinum group metal‐free oxygen pump is elaborated for the first time.