B, N Co‐Doped Three‐Dimensional Carbon Aerogels with Excellent Electrochemical Performance for the Oxygen Reduction Reaction

Abstract

Herein, an ordinary and mass‐production approach is reported to synthesize boron (B) and nitrogen (N) co‐doped three‐dimensional (3D) carbon aerogels (CA) by using glucose and borax as the raw materials by a simple hydrothermal method and then carbonization in NH3 atmosphere. The porous material (BN‐CA‐900) possesses a large specific surface area (1032 m2 g−1) and high contents of doped pyridinic N and graphitic N. The onset potential (0.91 V vs. reversible hydrogen electrode, RHE), half‐wave potential (0.77 V vs. RHE), and current density (5.70 mA cm−2 at 0.2 V vs. RHE) of BN‐CA‐900 for ORR are similar to those of commercial Pt/C, indicating that BN‐CA‐900 has a comparable catalytic activity with Pt/C in alkaline media. The number of electron transfer is 3.86–3.99 and the yield of hydrogen peroxide is less than 6.8 %. BN‐CA‐900 also presents decent catalytic performance in acidic medium. Moreover, the stability and methanol tolerance of BN‐CA‐900 are superior to commercial Pt/C in both alkaline and acidic media. The prepared BN‐CA‐900 is a promising candidate that may be applied in other areas, such as the adsorption of pollution, porous conductive electrodes, and lithium‐ion batteries.

3D Carbon Materials for Efficient Oxygen and Hydrogen Electrocatalysis

“…Indeed, given the number of possible sites in single heteroatom‐doped carbons already discussed, the addition of a second heteroatom complicates the picture somewhat. There are many recent examples in the literature of co‐doping with N of various different heteroatoms, including sulfur, phosphorous, boron, fluorine, and iodine …”

“…Florent et al showed that a high volume of small pores that adsorb O 2 enhances the ORR efficiency, and that the presence of B also helps the onset potential, contrary to what was previously shown on B‐doped CNTs, though the performance is significantly poorer than Pt/C in alkaline. Yu et al also synthesized N/B‐doped aerogels and tested them in alkaline as well as acid. The performance was comparable to Pt/C in alkaline, and showed significantly greater performance than the single N or B heteroatom‐doped versions of the catalyst.…”

“…Co‐doping has been shown to be a successful strategy to improve the activity of metal‐free catalysts, with several recent examples in the literature showing similar or better performance than Pt/C in alkaline, and even promising activity in acidic electrolytes . Co‐doping not only changes the delocalization of spin or charge density (electronic configuration changes) but also it creates more intrinsic defects in carbon atoms.…”

Cobalt Nanoparticles Embedded in N, S Co‐Doped Carbon towards Oxygen Reduction Reaction Derived by in situ Reducing Cobalt Sulfide

“…The high resolution C 1s spectra of CoSMe‐X‐800 samples (Figure a) show four different components of carbon at binding energy: 284.6 eV (C−C/C=C), 285.7 eV (C−S), 286.1 eV (C−N) and 288.4 eV (C=O) . In the sample of CoSMe‐0‐800, the peak of C−S is invisible due to no introduction of sulfur resources during the preparation process.…”

“…Furthermore, to enhance the attribution of doped heteroatoms to ORR activity, multiple kinds of heteroatoms are co‐doped into the system, working as the efficient electrocatalysts for ORR process. For example, Xie and co‐workers reported that B, N co‐doped metal free catalysts derived from cheap, ordinary and pollution‐free glucose and borax by using a simple hydrothermal process and then carbonization in NH 3 atmosphere. This catalyst is expected to be a candidate for novel high‐efficiency electrocatalysts in fuel cells.…”