Highly active hydrogen evolution catalysis on oxygen-deficient double-perovskite oxide PrBaCo2O6−δ. (9th April 2020)

• Record Type: Journal Article
• Authors: Togano, Hayato; Asai, Kaisei; Oda, Seiji; Ikeno, Hidekazu; Kawaguchi, Shogo; Oka, Kengo; Wada, Kouhei; Yagi, Shunsuke; Yamada, Ikuya
• Is Part Of: Materials chemistry frontiers. Volume 4:Number 5(2020)
• Page Start: 1519
• Page End: 1529
• Publication Date: 2020-04-09
• Subjects: Materials science -- Periodicals; Chemistry -- Periodicals; 540
• DOI: 10.1039/d0qm00056f
• Languages: English
• ISSNs: 2052-1529

Abstract

Abstract : Oxygen-deficient double perovskite oxides PrBaCo2 O6− δ exhibit highly active hydrogen evolution reaction catalysis, which is associated with multiple factors: oxygen deficiency, high Co valence, and A-site cation ordering. Abstract : Efficient hydrogen evolution on water splitting is a crucial issue to achieve a sustainable society based on renewable energy. Highly active and cost-effective catalysts for oxygen/hydrogen evolution reactions (OERs/HERs) are desired to suppress the intrinsically significant overpotential of these reactions. Perovskite-related transition-metal oxides have been widely investigated as promising candidates for electrochemical catalysts, whereas their complex composition and structure inhibit the elucidation of essential factors for activating HER. Herein, we report a systematic study on predominant factors affecting HER catalysis for Co-containing perovskite-related oxides. The A-site-ordered double perovskite oxide PrBaCo2 O6− δ exhibits HER activity with a volcano-type plot associated with oxygen deficiency content, and shows the highest activity at a moderate value of δ = 0.2, in addition to the significant superiority to the simple ABO3 -type perovskite, ACoO3 (A = La, La0.5 Ca0.5, Ca). Based on the Tafel slope, electric conductivity, and charge-transfer resistance analyses, we have found that complementary factors dominate the HER catalysis; Co–O covalency and water dissociation site, which are respectively induced by high Co valence and oxygen deficiency. This finding provides new insight into the rational design of transition-metal oxide catalysts for HER.