Catalytic wet air oxidation of toxic containments over highly dispersed Cu(II)/Cu(I)-N species in the framework of g-C3N4.

Catalytic wet air oxidation (CWAO) is a harmless, cheap and effective technology for the degradation of toxic containments directly to CO2 and H2O. In this work, highly dispersed Cu(II)/Cu(I)-N that embedded in the framework of g-C3N4 (Cux-g-C3N4) were synthesized in a facile thermal polymerization method and used in the CWAO of phenols, antibiotics and vitamins. Characterization results confirmed that g-C3N4 formed in the prepared catalyst and copper was chemically coordinated with N in g-C3N4, which inhibited the aggregation of copper. Meanwhile, Cu(II) or Cu(I) in the framework of g-C3N4 was more effective for the degradation of phenol than Cu(0) and CuO, and more than 23 toxic containments could be degraded under mild conditions. The prominent performance of Cu0.1-g-C3N4 for CWAO reaction was discussed on the base of these experiments and it was disclosed that in-situ formed H2O2 might be contributed to the highly activity.

Fabrication of metal-free two dimensional/two dimensional homojunction photocatalyst using various carbon nitride nanosheets as building blocks.

Semiconductor photocatalysis currently suffered three main problems, low solar energy utilization, high photo-generated charge recombination rate and the heavy metal ions release by the photo-corrosion. Herein, we developed a visible-light-driven homojunction photocatalyst with the metal-free two-dimensional (2D) graphitic carbon nitride nanosheets (CNNS). By employing liquid exfoliation and chemical blowing approaches, we obtained two kinds of CNNS materials (le-CNNS and cb-CNNS) with different band structures, and subsequently fabricated the homojunction photocatalyst. This 2D/2D nanocomposited homojunction photocatalyst exhibited enhanced photocatalytic performance compared to these individual 2D nanosheets materials. Moreover, its well universality and reusability were also demonstrated by photo-degradation of various organic pollutants and five successive runs. By studying the optical properties and the electrochemical behavior, the band alignment of this homojunction was illustrated and the possible mechanism was proposed, where the transmitted electrons on the conduction band (CB) of le-CNNS would transport to the CB of cb-CNNS, and the holes on the valence band (VB) of cb-CNNS transferred to the VB of le-CNNS, therefore promoting the photo-induced carrier separation. Additionally, the photoluminescence, electrochemical impendence and photocurrent measurements further demonstrated that the recombination of photo-excited electron-hole pairs had been efficiently suppressed in the homojunction and were respectively collected on different CNNS components.