Construction of LaNiO3 nanoparticles modified g-C3N4 nanosheets for enhancing visible light photocatalytic activity towards tetracycline degradation

Abstract Graphitic carbon nitride (g-C 3 N 4 ) with a suitable bandgap (ca. 2.7 eV) has been regarded as one of the most promising photocatalysts for water purification. Nevertheless, pristine g-C 3 N 4 still suffered from low photocatalytic performance due to the high recombination of the photoinduced charge carriers. To this end, we designed and constructed a direct Z-scheme LaNiO 3 /g-C 3 N 4 hybrid composed of LaNiO 3 nanoparticles and g-C 3 N 4 nanosheets through a facile heat treatment method. As expected, the resultant LaNiO 3 /g-C 3 N 4 hybrid demonstrated drastically improved photocatalytic performance of tetracycline (TC) degradation in aqueous solution under visible light irradiation (λ > 420 nm). Strikingly, the optimized LaNiO 3 (30 wt%)/g-C 3 N 4 composite exhibited prominent photocatalytic activity for TC degradation under visible light irradiation, the TC degradation rate up to 0.00282 min −1 , which was about 3.8 and 3.9 times larger than those of pure g-C 3 N 4 and pristine LaNiO 3 , respectively. The enhanced photocatalytic activity was mainly ascribed to the formation of the direct Z-scheme LaNiO 3 /g-C 3 N 4 heterojunction as a result of the synergistic effect between LaNiO 3 and g-C 3 N 4 , which not only facilitated the interfacial charge transfer efficiency but also preserved the strong redox ability of the photogenerated electrons and holes. Furthermore, active species trapping experiments confirmed that the synergistic effect of superoxide radicals and holes was responsible for the photodegradation of TC. Eventually, a plausible Z-scheme charge transfer mechanism was put forward based on the experimental results. This work provides a new approach to construct highly efficient Z-scheme g-C 3 N 4 -based composite photocatalysts for environmental remediation and energy conversion.