title: Porous Iron-Tungsten Carbide Electrocatalyst with High Activity and Stability toward Oxygen Reduction Reaction: From the Self-Assisted Synthetic Mechanism to Its Active-Species Probing.
abstract: We synthesized a novel nonprecious metal electrocatalyst by pyrolysis of a colloid mixture consisting of a tungsten source and phenolic resin, with the simultaneous addition of ferric salt. The rationally designed electrocatalyst has a unique structure, with nanosized WC and Fe3W3C uniformly dispersed in a three-dimensional porous carbon framework. WC, which was thought difficult to produce, is successfully prepared at a relatively low temperature of about 750 °C at an inert atmosphere. XRD studies demonstrate the self-assisted effect of Fe, which accelerates the formation of WC, getting around the pathway of direct carbonaceous reduction of tungsten by carbon. The porous iron-tungsten carbide (Fe-W-C) nanocomposite as electrocatalyst shows excellent ORR activity with the onset and half-wave potentials of 0.864 and 0.727 V (vs RHE), respectively, which are close to those of Pt/C (0.976 and 0.820 V vs RHE). Electrochemical measurements show that Fe-W-C follows almost the effective four-electron-transfer pathway and would not be disturbed by methanol. The presence of a protective graphite shell outside the active carbide cores substantially improves the durability of the electrocatalyst. Both the removal of Fe species and the absence of W species would severely degrade the activity, while halide ions Cl-and sulfur-containing species SCN-can significantly suppress the ORR activity by the blocking of Fe species. These facts indicate that the ORR active species of Fe-W-C should be relevant to both W and Fe species.
authors.affiliation: College of Materials Science and Technology, Jiangsu Key Laboratory of Materials and Technology for Energy Conversion, Nanjing University of Aeronautics and Astronautics , 210016 Nanjing, P. R. China.
authors.forename: Li
authors.initials: L
authors.lastname: Song
authors.affiliation: College of Materials Science and Technology, Jiangsu Key Laboratory of Materials and Technology for Energy Conversion, Nanjing University of Aeronautics and Astronautics , 210016 Nanjing, P. R. China.
authors.forename: Tao
authors.initials: T
authors.lastname: Wang
authors.affiliation: College of Materials Science and Technology, Jiangsu Key Laboratory of Materials and Technology for Energy Conversion, Nanjing University of Aeronautics and Astronautics , 210016 Nanjing, P. R. China.
authors.forename: Yilin
authors.initials: Y
authors.lastname: Wang
authors.affiliation: College of Materials Science and Technology, Jiangsu Key Laboratory of Materials and Technology for Energy Conversion, Nanjing University of Aeronautics and Astronautics , 210016 Nanjing, P. R. China.
authors.forename: Hairong
authors.initials: H
authors.lastname: Xue
authors.affiliation: College of Materials Science and Technology, Jiangsu Key Laboratory of Materials and Technology for Energy Conversion, Nanjing University of Aeronautics and Astronautics , 210016 Nanjing, P. R. China.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Fan
authors.affiliation: College of Materials Science and Technology, Jiangsu Key Laboratory of Materials and Technology for Energy Conversion, Nanjing University of Aeronautics and Astronautics , 210016 Nanjing, P. R. China.
authors.forename: Hu
authors.initials: H
authors.lastname: Guo
authors.affiliation: College of Materials Science and Technology, Jiangsu Key Laboratory of Materials and Technology for Energy Conversion, Nanjing University of Aeronautics and Astronautics , 210016 Nanjing, P. R. China.
authors.forename: Wei
authors.initials: W
authors.lastname: Xia
authors.affiliation: College of Materials Science and Technology, Jiangsu Key Laboratory of Materials and Technology for Energy Conversion, Nanjing University of Aeronautics and Astronautics , 210016 Nanjing, P. R. China.
authors.forename: Hao
authors.initials: H
authors.lastname: Gong
authors.affiliation: College of Materials Science and Technology, Jiangsu Key Laboratory of Materials and Technology for Energy Conversion, Nanjing University of Aeronautics and Astronautics , 210016 Nanjing, P. R. China.
authors.forename: Jianping
authors.identifier: http://orcid.org/0000-0001-7525-2809
authors.initials: J
authors.lastname: He
keywords: carbide; high durability; mesoporous carbon; methanol tolerant; oxygen reduction reaction