Three-Dimensional Phosphorus-Doped Graphitic-C3N4Self-Assembly with NH2-Functionalized Carbon Composite Materials for Enhanced Oxygen Reduction Reaction.
Oxygen reduction reaction (ORR) is the major reaction that occurs at the cathodes of fuel cells and metal-air batteries. Development of inexpensive, active, and durable heteroatom doped carbon-based ORR catalysts can lead to significant cost reduction of these electrochemical energy devices, which therefore has recently attracted enormous research attentions. This work reports a three-dimensional porous composite (P-g-C3N4@NH2-CB) for the highly efficient ORR catalyst. P-g-C3N4@NH2-CB was prepared by mixing phosphorus-doped graphitic carbon nitride nanosheets (P-g-C3N4NSs) with NH2-functionalized carbon black (NH2-CB) via a novel self-assembly approach. The NH2-CB was rationally chosen as the spacer that enables the self-assembled with the P-g-C3N4NSs driven by the electrostatic interaction. The intercalation of NH2-CB induces the transformation of 2-D P-g-C3N4NSs into a 3-D composites material of higher surface area, thereby exposing more ORR active sites. The P-g-C3N4@NH2-CB exhibited a remarkable ORR activity with an electron transfer number of 3.83 and Tafel slope of 89 mV dec-1in alkaline electrolyte, which is comparable to the ORR performance on Pt/Vulcan XC-72. It is found that the incorporated P atoms as well as employing NH2-CB spacer not only reduces the overpotential of ORR, but also enhances the ORR activity of carbon nitride-based materials, owing to the synergistic effect between P and N in tri-s-triazine rings of carbon nitrides and the optimum interaction between the oppositely charged P-g-C3N4and NH2-CB.
Chemical and Biological Engineering, Biorenewables Research Laboratory, Iowa State University , Ames, Iowa50011, United States.
Yang
Y
Qiu
Department of Mechanical Engineering, Purdue School of Engineering and Technology, Indiana University-Purdue University Indianapolis , Indianapolis, Indiana46202, United States.
Le
L
Xin
Chemical and Biological Engineering, Biorenewables Research Laboratory, Iowa State University , Ames, Iowa50011, United States.
Fan
F
Jia
Department of Mechanical Engineering, Purdue School of Engineering and Technology, Indiana University-Purdue University Indianapolis , Indianapolis, Indiana46202, United States.
Jian
J
Xie
Chemical and Biological Engineering, Biorenewables Research Laboratory, Iowa State University , Ames, Iowa50011, United States.|US DOE Ames Lab , Ames, Iowa50011, United States.
Wenzhen
W
Li