Visible-light-responsive graphitic carbon nitride: Rational design and photocatalytic applications for water treatment

Qinmin Zheng, David P. Durkin, Justin E. Elenewski, Yingxue Sun, Nathan A. Banek, Likun Hua, Hanning Chen, Michael J. Wagner, Wen Zhang, Danmeng Shuai

Research output: Contribution to journalArticlepeer-review

147 Scopus citations

Abstract

Graphitic carbon nitride (g-C3N4) has recently emerged as a promising visible-light-responsive polymeric photocatalyst; however, a molecular-level understanding of material properties and its application for water purification were underexplored. In this study, we rationally designed nonmetal doped, supramolecule-based g-C3N4 with improved surface area and charge separation. Density functional theory (DFT) simulations indicated that carbon-doped g-C3N4 showed a thermodynamically stable structure, promoted charge separation, and had suitable energy levels of conduction and valence bands for photocatalytic oxidation compared to phosphorus-doped g-C3N4.The optimized carbon-doped, supramoleculebased g-C3N4 showed a reaction rate enhancement of 2.3−10.5-fold for the degradation of phenol and persistent organic micropollutants compared to that of conventional, melamine-based g-C3N4 in a model buffer system under the irradiation of simulated visible sunlight. Carbon-doping but not phosphorus-doping improved reactivity for contaminant degradation in agreement with DFT simulation results. Selective contaminant degradation was observed on g-C3N4, likely due to differences in reactive oxygen species production and/or contaminant-photocatalyst interfacial interactions on different g-C3N4 samples. Moreover, g-C3N4 is a robust photocatalyst for contaminant degradation in raw natural water and (partially)treated water and wastewater. In summary, DFT simulations are a viable tool to predict photocatalyst properties and oxidation performance for contaminant removal,and they guide the rational design, fabrication,and implementation of visible-light-responsive g-C3N4 for efficient, robust,and sustainable water treatment.

Original languageEnglish (US)
Pages (from-to)12938-12948
Number of pages11
JournalEnvironmental Science and Technology
Volume50
Issue number23
DOIs
StatePublished - Dec 6 2016

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Environmental Chemistry

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