Atomic Co decorated free-standing graphene electrode assembly for efficient hydrogen peroxide production in acid. Issue 3 (27th January 2022)

• Record Type: Journal Article
• Authors: Lin, Zeheng; Zhang, Qingran; Pan, Jian; Tsounis, Constantine; Esmailpour, Ali Asghar; Xi, Shibo; Yang, Hui Ying; Han, Zhaojun; Yun, Jimmy; Amal, Rose; Lu, Xunyu
• Is Part Of: Energy & environmental science. Volume 15:Issue 3(2022)
• Page Start: 1172
• Page End: 1182
• Publication Date: 2022-01-27
• Subjects: Energy conversion -- Periodicals; Fuel switching -- Periodicals; Environmental sciences -- Periodicals; Environmental chemistry -- Periodicals; 333.79
• DOI: 10.1039/d1ee02884g
• Languages: English
• ISSNs: 1754-5692

Abstract

Abstract : A novel oxygen reduction reaction (ORR) electrode comprising isolated Co atom decorated vertically aligned graphene nanosheets is designed, which can enable the most energy-efficient, rapid acidic H2 O2 production in a flow-cell reactor. Abstract : Electrochemical oxygen reduction reaction (ORR) in acids via a selective 2e − pathway offers great opportunities for electrosynthesis of H2 O2, allowing on-site environmental treatment in industry. Unfortunately, despite some progress, the apparent activity of most electrocatalysts (especially in a flow cell reactor) still requires further improvement to meet the industrial demands, where high H2 O2 productivity with low energy input is desired. Herein, we report a free-standing ORR electrode comprising cobalt single atoms on a vertically aligned graphene nanosheet assembly (CoN4 /VG), which is demonstrated to exhibit a hierarchical porous structure maximizing the utilization of catalytic active atoms without sacrificing the mass/charge transport efficiencies. Within a H-cell setup, the as-prepared ORR electrode gives a H2 O2 selectivity close to 100% from 0.3 to 0.5 V versus reversible hydrogen electrode (RHE) in 0.1 M HClO4, sustaining a record-breaking H2 O2 productivity of 706 mmolH2 O2 gcatalyst −1 h −1 at 0.3 V vs. RHE for 36 hours. Further employing this electrode in a gas-diffusion flow reactor yields a peroxide concentration of 1100 mg L −1 (4000 mmolH2 O2 gcatalyst −1 h −1 ) continuously at −1.8 V of cell voltage, corresponding to an energy consumption of 3.81 W h gH2 O2 −1, which represents the most energy-efficient flow system for rapid H2 O2 generation in acidic media.