Chemical Identification of Catalytically Active Sites on Oxygen‐doped Carbon Nanosheet to Decipher the High Activity for Electro‐synthesis Hydrogen Peroxide

Abstract

Electrochemical production of hydrogen peroxide (H 2 O 2 )t hrough two-electron (2 e À )o xygen reduction reaction (ORR) is an on-site and clean route.O xygen-doped carbon materials with high ORR activity and H 2 O 2 selectivity have been considered as the promising catalysts,h owever,t here is still alackofdirect experimental evidence to identify true active sites at the complex carbon surface.H erein, we propose ac hemicalt itration strategy to decipher the oxygen-doped carbon nanosheet (OCNS 900 )c atalyst for 2e À ORR. The OCNS 900 exhibits outstanding 2e À ORR performances with onset potential of 0.825 V( vs.R HE), mass activity of 14.5 Ag À1 at 0.75 V( vs.R HE) and H 2 O 2 production rate of 770 mmol g À1 h À1 in flow cell, surpassing most reported carbon catalysts.Through selective chemical titration of C = O, C À OH, and COOH groups,wefound that C = Ospecies contributed to the most electrocatalytic activity and were the most active sites for 2e À ORR, which were corroborated by theoretical calculations.

Aerophilic Triphase Interface Tuned by Carbon Dots Driving Durable and Flexible Rechargeable Zn-Air Batteries

“…The O K-edge NEXAFS spectra of Co@C–O–Cs in Fig. 3 d exhibit three characteristic peaks, including π*(COO − ) (530.2 eV), π*(C = O) (531.6 eV), and σ*(C–O–C) (541.7 eV), respectively [ 72 , 73 ]. The Co K-edge X-ray absorption near edge structure spectrum of Co@C–O–Cs shows a pre-edge feature at 7708 eV, which is attributed to the 1 s → 3 d electron transition (Fig.…”

“…The Co L-edge NEXAFS spectra of Co@C-O-Cs (Fig. 3c [72,73]. The Co K-edge X-ray absorption near edge structure spectrum of Co@C-O-Cs shows a pre-edge feature at 7708 eV, which is attributed to the 1s → 3d electron transition (Fig.…”

F127-assisted preparation of FeCo nanoalloys encapsulated in nitrogen-doped carbon for efficient oxygen reduction reaction

“…5,6 In this context, a great number of investigations focusing on non-precious ORR electrocatalysts have been carried out, such as transition-metal oxides, carbides, phosphides, selenides and nitrogen-doped carbon materials. [7][8][9][10][11][12][13][14][15][16][17][18] Recently, carbon materials modified with transition metals (e.g., Fe and Co) and heteroatoms (e.g., N and S) have attracted a great deal of attention as alternatives to Pt-based catalysts. 5,19 Among them, Co-N-C materials are regarded as one of the most promising platinum-free electrocatalysts due to their good activity and operational stability over a reasonable service life.…”

“…5,6 In this context, a great number of investigations focusing on non-precious ORR electrocatalysts have been carried out, such as transition-metal oxides, carbides, phosphides, selenides and nitrogen-doped carbon materials. 7–18 Recently, carbon materials modified with transition metals ( e.g. , Fe and Co) and heteroatoms ( e.g.…”

Atomically Dispersed s‐Block Magnesium Sites for Electroreduction of CO2 to CO

“…To investigate high-current performance for the practical application of CO 2 RR, we incorporated Mg-C 3 N 4 to fabricate flow cell in Figure S38. [17] The gas diffusion electrodes with Mg-C 3 N 4 shows a large current density of 300 mA cm À2 in flow cell, under high CO Faradaic efficiency ! 90 % (Figure 4 d).…”