Carbon Free and Noble Metal Free Ni2Mo6S8 Electrocatalyst for Selective Electrosynthesis of H2O2. (28th August 2021)

• Record Type: Journal Article
• Authors: Xia, Fan; Li, Bomin; Liu, Yiqi; Liu, Yuzi; Gao, Siyuan; Lu, Ke; Kaelin, Jacob; Wang, Rongyue; Marks, Tobin J.; Cheng, Yingwen
• Is Part Of: Advanced functional materials. Volume 31:Number 47(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-08-28
• Subjects: carbon free -- earth abundant -- hydrogen peroxide -- oxygen reduction -- selective electrocatalysis; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.202104716
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: Electrocatalytic two‐electron reduction of oxygen is a promising method for producing sustainable H2 O2 but lacks low‐cost and selective electrocatalysts. Here, the Chevrel phase chalcogenide Ni2 Mo6 S8 is presented as a novel active motif for reducing oxygen to H2 O2 in an aqueous electrolyte. Although it has a low surface area, the Ni2 Mo6 S8 catalyst exhibits exceptional activity for H2 O2 synthesis with >90% H2 O2 molar selectivity across a wide potential range. Chemical titration verified successful generation of H2 O2 and confirmed rates as high as 90 mmol H2 O2 gcat −1 h −1 . The outstanding activities are attributed to the ligand and ensemble effects of Ni that promote H2 O dissociation and proton‐coupled reduction of O2 to HOO*, and the spatial effect of the Chevrel phase structure that isolates Ni active sites to inhibit OO cleavage. The synergy of these effects delivers fast and selective production of H2 O2 with high turn‐over frequencies of ≈30 s −1 . In addition, the Ni2 Mo6 S8 catalyst has a stable crystal structure that is resistive for oxidation and delivers good catalyst stability for continuous H2 O2 production. The described Ni‐Mo6 S8 active motif can unlock new opportunities for designing Earth‐abundant electrocatalysts to tune oxygen reduction for practical H2 O2 production. Abstract : A new active motif based on H2 O2 Ni2 Mo6 S8 is reported for electrochemical synthesis with ≈98% selectivity. The activity originates from ligand and ensemble effects of Ni that promote O2 reduction to HOO* and a spatial effect that inhibits OO cleavage. The catalyst exhibits a high turn‐over frequency of ≈30 s −1 and produced H2 O2 at 90 mmol gcat −1 h −1 .