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Oxygenated boron-doped carbon via polymer dehalogenation as an electrocatalyst for high-efficiency O2 reduction to H2O2

03.15.22 | Science China Press

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(A) The schematic diagram of the synthesis of B-doped carbon via polymer dehalogenation strategy. (B) SEM image of O-BC-2-650, and (C) HR-TEM image of O-BC-2-650.
PVDC undergoes dehalogenation in the presence of KOH, removing Cl and H functional groups to generate the clean byproducts KCl and H2O. The dehalogenated carbon sites exhibit very high reactivity, coupling with H3BO3 to form C–B or C–O–B bonding. Thereafter, the B-doped C is obtained by inert annealing B-doped polymeric C. The SEM and HRTEM images of O-BC-2-650, which evidence a 3D interconnected porous structure and an amorphous state with short-range graphitization. Moreover, the uniform distr Credit: ©Science China Press

Recently, Professor Zhang Guoxin from Shandong University of Science and Technology and Dr. Chang Yingna from Yancheng Teacher University published a paper entitled "Oxygenated boron-doped carbon via polymer dehalogenation as an electrocatalyst for high-efficiency O 2 reduction to H 2 O 2 " in Science China Materials . In this study, a cheap, simple, and environmentally friendly method is developed for the preparation of B-doped carbon materials, and their application in the electrocatalytic synthesis of H 2 O 2 is investigated. Boron has a lower electronegativity (2.04) than that of carbon (2.55). Thus, the B site is positively charged when situated adjacently to a C site, facilitating the chemisorption of O 2 molecules. Therefore, B-doped carbon is synthesized by strategic organic dehalogenation during the synthesis process, specifically using polyvinyldichloride as the carbon source, KOH as the dehalogenating agent, and boric acid as the dopant source. Controlling the composition and morphological structure of the boron-doped carbon by systematic variation of the H 3 BO 3 dosage and annealing temperature leads to optimized material synthesis parameters and optimal H 2 O 2 selectivity.

Electrochemical measurements revealed that the optimal O-BC-2-650 exhibited a selectivity of 98% for the 2e − oxygen reduction to H 2 O 2 and an average H 2 O 2 production rate of 412.8 mmol g cat. −1 h −1 in an H-type alkaline. Density functional theory simulations indicated that the functionalization of active B sites with one oxygen atom provides the lowest Gibbs free energy change (ΔG) of 0.03 eV for the hydrogenation of * O 2 , while functionalization with zero or two O atoms results in much larger ΔG values (0.08 and 0.10 eV, respectively). Thus, the insertion of B–O species into a carbon matrix significantly enhances its catalytic performance for the electrochemical synthesis of H 2 O 2 . This work provides a promising low-cost electrocatalyst for the electrocatalytic synthesis of H 2 O 2 , and reveals the feasibility of B-doped carbon catalysts in practical applications, providing new ideas for the design and application of various advanced metal-free doped carbon catalysts.

See the article:

Oxygenated boron-doped carbon via polymer dehalogenation as an electrocatalyst for high-efficiency O 2 reduction to H 2 O 2

https://doi.org/10.1007/s40843-021-1891-2

Science China Materials

10.1007/s40843-021-1891-2

5-Jan-2022

Additional Media

XPS characterizations of O-C-650 and O-BC-2-650: (A) XPS survey and element content, (B) C 1s spectra, (C) O 1s spectra, and (D) B 1s spectra.
The atomic percentage of B in O-BC-2-650 was 5.3at%. The C 1s and O 1s spectra of O-BC-2-650 and O-C-650 revealed the content of C and O and their forms are essentially the same. Notably, the percentage of O–BC2 in O-BC-2-650 is 23.8%, which is higher than that in RT-O-BC-2 (19.8%). The homogeneous distribution of boron-oxygen-carbon structures can also enhance the wettability and durability of a carbon surface and improve the electrochemical activity of a carbon substrate. Credit: ©Science China Press
Oxygen reduction performance of O-C-650, O-BC-0.5-650, O-BC-1-650, O-BC-2-650, and O-BC-3-650 in 0.1 mol L−1 KOH solution: (A) LSV curves, (B) the number of transferred electrons as a function of the potential, (C) calculated H2O2 selectivity, and (D) H2O
The effect of the amount of dopant source boric acid used on the performance of the ORR is investigated. The H2O2 yields for the samples decrease in the order of O-BC-2-650 > O-BC-1-650 > O-BC-0.5-650 > O-BC-3-650 > O-C-650, indicating that B doping is beneficial to 2e− ORR selectivity. Credit: ©Science China Press
DFT results of the 2e− ORR activities on O-BC-2-650. (A) Different boron-doped types were examined. The carbon atoms or boron atoms denoted by a red circle are the active sites under investigation, (B) ∆GHOO* for 2e− ORR to H2O2 at the equilibrium potenti
13 models have been proposed, of which seven possible site models represent BC3, three site models represent BC2O, and three site models represent BCO2. Most sites weakly bind OOH*, making step (1) the rate-determining step (RDS). For site No. 1, which binds OOH* more strongly, step (2) becomes the RDS. The B site in the BC2O structure is closest to the peak of the volcano and can thus be considered a representative 2e− ORR active site, typically with an overpotential of 0.028 V. Credit: ©Science China Press

Keywords

Physical Sciences

Article Information

Journal
Science China Materials
DOI
10.1007/s40843-021-1891-2
Article Publication Date
2022-01-05

Contact Information

Bei Yan
Science China Press
yanbei@scichina.org

How to Cite This Article

APA:
Science China Press. (2022, March 15). Oxygenated boron-doped carbon via polymer dehalogenation as an electrocatalyst for high-efficiency O2 reduction to H2O2. Brightsurf News. https://www.brightsurf.com/news/1ZZVV251/oxygenated-boron-doped-carbon-via-polymer-dehalogenation-as-an-electrocatalyst-for-high-efficiency-o2-reduction-to-h2o2.html
MLA:
"Oxygenated boron-doped carbon via polymer dehalogenation as an electrocatalyst for high-efficiency O2 reduction to H2O2." Brightsurf News, Mar. 15 2022, https://www.brightsurf.com/news/1ZZVV251/oxygenated-boron-doped-carbon-via-polymer-dehalogenation-as-an-electrocatalyst-for-high-efficiency-o2-reduction-to-h2o2.html.