Comparison of Graphitic Carbon Nitrides Synthetized from Melamine and Melamine-Cyanurate Complex: Characterization and Photocatalytic Decomposition of Ofloxacin and Ampicillin.

Petr Praus,Kryštof Foniok,Aneta Smýkalová

doi:10.3390/ma14081967

Abstract

Graphitic carbon nitride (g-C3N4, hereafter abbreviated as CN) was prepared by the heating of melamine (CN-M) and melamine-cyanurate complex (CN-MCA), respectively, in air at 550 °C for 4 h. The specific surface area (SSA) of CN-M and CN-MCA was 12 m2 g−1 and 225 m2g−1 and the content of oxygen was 0.62 wt.% and 1.88 wt.%, respectively. The band gap energy (Eg) of CN-M was 2.64 eV and Eg of CN-MCA was 2.73 eV. The photocatalytic activity of the CN materials was tested by means of the decomposition of antibiotics ofloxacin and ampicillin under LED irradiation of 420 nm. The activity of CN-MCA was higher due to its high SSA, which was determined based on the physisorption of nitrogen. Ofloxacin was decomposed more efficiently than ampicillin in the presence of both photocatalysts.

Highlights

Graphitic carbon nitride (CN) is a metal-free semiconducting material that has been intensively studied during the last decade
Their photocatalytic activity was investigated by the photocatalytic decomposition of ofloxacin and ampicillin
Using the different precursors of CN such as melamine and MCA, the composition of final graphitic carbon nitrides was determined for comparison

Summary

Introduction

Graphitic carbon nitride (CN) is a metal-free semiconducting material that has been intensively studied during the last decade. Chemical, and thermal stability and capability to absorb visible irradiation (band gap energy of about 2.7 eV) predetermine this material for many medical [1,2], industrial [3,4], and environmental applications [5,6,7,8,9]. Graphitic carbon nitride can be synthetized from simple nitrogen-rich organic compounds such as melamine, cyanamide, dicyanamide, urea, thiourea, etc. We report on a comparison of CN synthetized from common melamine and from the complex of melamine and cyanuric acid called melamine-cyanurate (MCA). Melamine (M) and cyanuric acid (CA) form an insoluble MCA complex [15] as follows: iations CN based materials can be used as photocatalysts [10,11], biosensors [12] and chemical sensors [13] and as materials for biomedical applications [14], energy and environmental applications [4], etc.

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