Catalyst-Free Synthesis of Crumpled Boron and Nitrogen Co-Doped Graphite Layers with Tunable Bond Structure for Oxygen Reduction Reaction

Abstract

Two-dimensional materials based on ternary system of B, C and N are useful ranging from electric devices to catalysis. The bonding arrangement within these BCN nanosheets largely determines their electronic structure and thus chemical and (or) physical properties, yet it remains a challenge to manipulate their bond structures in a convenient and controlled manner. Recently, we developed a synthetic protocol for the synthesis of crumpled BCN nanosheets with tunable B and N bond structure using urea, boric acid and polyethylene glycol (PEG) as precursors. By carefully selecting the synthesis condition, we can tune the structure of BCN sheets from s-BCN with B and N bond together to h-BCN with B and N homogenously dispersed in BCN sheets. Detailed experiments suggest that the final bond structure of B and N in graphene depends on the preferentially doped N structure in BCN nanosheets. When N substituted the in-plane carbon atom with all its electrons configured into the π electron system of graphene, it facilitates the formation of h-BCN with B and N in separated state. On the contrary, when nitrogen substituted the edge-plane carbon with the nitrogen dopant surrounded with the lone electron pairs, it benefits for the formation of B-N structure. Specially, the compound riched with h-BCN shows excellent ORR performance in alkaline solution due to the synergistic effect between B and N, while s-BCN dominant BCN shows graphite-like activity for ORR, suggesting the intrinsic properties differences of BCN nanosheets with different dopants bond arrangement.

N-doped crumpled graphene: bottom-up synthesis and its superior oxygen reduction performance

“…2b reproduces the linear scanning voltammetry (LSV) curve for the CrG-900, showing a highly comparable onset and even better half-wave potential to those of the Pt/C electrode, but left big gap of limiting current density being much less than that of 20 wt.% Pt/C. The CrG-900 exhibited advanced onset and half-wave potentials than that of the previously reported CrG which made by the conventional top-down methods (Table S1) [51][52][53][54][55]. Fig.…”

Earth‐Abundant Nanomaterials for Oxygen Reduction

“…has also been identified as an important approach to improve the spin and charge density of the graphene surface. [207][208][209][210] Several methods have been used to dope graphene with these heteroatoms,including CVD,ball milling, thermal annealing, and wet chemical methods. [211] Thep resence of edges in the graphitic plane is suggested to be important for ORR because edges offer maximum exposure to the catalytic sites.…”

Non-Precious Electrocatalysts for Oxygen Reduction Reaction in Alkaline Media: Latest Achievements on Novel Carbon Materials

“…Urea with boric acid and polyethylene glycol were used for the preparation of B-N-co-doped graphite layers [48]. The obtained ORR kinetic current density was ca 27.0 mA·cm −2 , while its half-wave potential was very satisfactory; ca 0.707 V vs. RHE.…”

“…Its excellent activity was mainly attributed to the following factors: (i) the doping effect of N and Co; (ii) the porous structure; and (iii) the good contact between N/Co-doped carbon polyhedron and nitrogen-doped reduced graphene oxide. [58], [53], [55], [56], [49], [47], [50], [51], [59], [54], [57], [48], [52]). [58], [53], [55], [56], [49], [47], [50], [51], [59], [54], [57], [48], [52]).…”