Biomass-derived nitrogen self-doped porous carbon as effective metal-free catalysts for oxygen reduction reaction

Abstract

Biomass-derived nitrogen self-doped porous carbon was synthesized by a facile procedure based on simple pyrolysis of water hyacinth (eichhornia crassipes) at controlled temperatures (600-800 °C) with ZnCl2 as an activation reagent. The obtained porous carbon exhibited a BET surface area up to 950.6 m(2) g(-1), and various forms of nitrogen (pyridinic, pyrrolic and graphitic) were found to be incorporated into the carbon molecular skeleton. Electrochemical measurements showed that the nitrogen self-doped carbons possessed a high electrocatalytic activity for ORR in alkaline media that was highly comparable to that of commercial 20% Pt/C catalysts. Experimentally, the best performance was identified with the sample prepared at 700 °C, with the onset potential at ca. +0.98 V vs. RHE, that possessed the highest concentrations of pyridinic and graphitic nitrogens among the series. Moreover, the porous carbon catalysts showed excellent long-term stability and much enhanced methanol tolerance, as compared to commercial Pt/C. The performance was also markedly better than or at least comparable to the leading results in the literature based on biomass-derived carbon catalysts for ORR. The results suggested a promising route based on economical and sustainable biomass towards the development and engineering of value-added carbon materials as effective metal-free cathode catalysts for alkaline fuel cells.

Coprinus comatus-derived nitrogen-containing biocarbon electrocatalyst with the addition of self-generating graphene-like support for superior oxygen reduction reaction

“…For further study, we compared the ORR catalytic property of N-BC@G-900 with other catalysts [13,14,17,21,35,36,38], as displayed in Table S1 (online). Our results are comparable with those of the best N-doped carbon catalysts reported to date in terms of E ORR , half-wave potential, average electron transfer number (n) and limited current density, but the BET surface area of the N-BC@G-900 catalyst is much lower than that of numerous nitrogen-doped carbon catalysts [16,33,34]. In fact, the major reason for the electrocatalytic activity enhancement is the density of surface active sites rather than the total surface area, although the significance of the BET specific surface area cannot be ruled out totally [31].…”

“…One widely used strategy for synthesis of the doped carbon catalysts is to use natural biomass as a nitrogen source of active centers or a direct precursor [15,16]. Several typical biomass precursors, previously reported in the literatures, include soybean [17], pig bone [18], silk fibroin [19], nori [20], blood protein [21], and hemoglobin [22].…”

Sol–gel carbons from ionothermal syntheses

“…Fischer et al [15] extensively studied the solubility of cellulose in metal chloride hydrate melts. In fact, it was recently shown that cheap and abundant biomass can also be used for the synthesis of structurally very similar materials [22][23][24][25][26]. In other work, LiCl/KCl, cesium acetate or Na 2 CO 3 /K 2 CO 3 melts were used as flux to obtain oligographene, carbon gels or active carbon [27][28][29].…”

A Hierarchically Porous Carbon Fabric for Highly Sensitive Electrochemical Sensors

“…Porous materials have received a great deal of attention since it poses the high specific surface area, diverse porous structure, stability in different chemical environments, and easy accessibility, [1] which can be used for gas adsorption or liquid separation, [2] catalysis, [3] electric, [4] and battery [5] fields. In addition to the porosity, the conductivity and hydrophilicity are major key factors for the case of electrochemical sensors or biosensors used in biochemical applications such as the detection of H 2 O 2 or methanol.…”