A Novel Metal-Free Polymer-Based POPD/g-C3N4 Photocatalyst with Enhanced Charge Carrier Separation for the Degradation of Tetracycline Hydrochloride

Development of low-cost, highly-efficient and metal-free photocatalyst has been attracted great attentions recently owing to its unique advantages and wide application. Here, the novel metal-free Poly-o-phenylenediamine (POPD)/g-C3N4 photocatalyst is firstly synthetized via suspension polymerization in the existence of g-C3N4. Such POPD/g-C3N4 photocatalyst is constructed through growth of highly dispersed conductive polymer nanoparticles on the g-C3N4 surfaces. The photoluminescent spectra and photoelectrochemical measurement confirm that the introduction of POPD nanoparticles in g-C3N4 system can effectively separate charge carrier and suppress their recombination. As expected, the as-prepared POPD/g-C3N4 photocatalyst exhibits obviously enhanced photocatalytic degradation performance of tetracycline hydrochloride than that of pure g-C3N4 under visible light irradiation, which is due to the synergistic effect of POPD and g-C3N4. At last, the possible photocatalytic reaction mechanism and the transfer and separation process of photo-generated charge carriers in the POPD/g-C3N4 system are proposed. This work provides a new insight into the construction of other metal-free polymer-based photocatalyst for water purification.