One-step synthesis of Mg-doped g-C3N4 nanosheets for efficient photo-Fenton-like catalysis

Recently, the design of efficient and environmentally friendly photo-Fenton-like catalysts has attracted much attention in the field of environmental remediation. In this work, Mg-doped graphitic carbon nitride (g-C3N4) nanosheets (MgCNNS) were fabricated using the thermal polymerization of melamine and MgCl2 with the assistance of the NH4Cl chemical blowing method. MgCNNS were used to activate H2O2 to degrade methylene blue (MB) under visible-light illumination. Results showed that the maximum reaction rate constant of MgCNNS was 24 times higher than that of pristine g-C3N4. The notable improvement in catalytic properties was attributed to the synergistic effect between photocatalysis and Fenton-like reaction. The strong adsorption and transfer ability of NMg bond to electrons not only effectively inhibited the recombination of photoinduced carriers, but also promoted the conversion of H2O2 into reactive oxygen species in the Fenton-like reaction. The influences of different reaction parameters (i.e., catalyst dosage, H2O2 dosage, pH value, MB concentration, and coexisting substance) on the catalytic properties in MB degradation were studied. Moreover, the MgCNNS catalyst had the characteristics of high stability, wide pH range, nontoxicity, low cost, and easy manufacturing and is a promising candidate for the treatment of organic contaminants in water. [Display omitted] •An efficient and environmentally friendly photo-Fenton-like catalyst was synthesized by a simple one-step method.•The NMg bond in the Mg-doped g-C3N4 nanosheets plays a vital role in the photo-Fenton-like reaction.•The synergy between photocatalysis and Fenton-like process helps to yield abundant reactive radicals, such as 1O2, •O2−, h+, and •OH.