Synergy of vacancy engineering and surface plasmon modification for improving the photocatalytic performance of La2Ti2O7 with a broad band gap†
Abstract
A novel AgCl/Ag/OV-La2Ti2O7 (AAOL) photocatalyst was prosperously synthesized by growing plasmonic Ag/AgCl on the surface of OV-La2Ti2O7, in which La2Ti2O7 containing oxygen vacancies (OV-La2Ti2O7) was prepared using a thermal reduction method. The results of degradation experiment showed that the AAOL composite presented excellent visible photodegradation performance for tetracycline hydrochloride (TC), and the TC removal efficiency reached 96.8% within 60 minutes. And the degradation kinetic constant of AAOL was approximately 3.96 times that of OV-La2Ti2O7 and 6.06 times that of Ag/AgCl. This was facilitated by the co-contribution of vacancy engineering and surface plasmon modification, which extended the absorption range to visible light, increased the charge transfer rate and promoted the separation of charge-carriers. In addition, the degradation intermediates of TC were studied using the HPLC-MS technique. A possible Z-scheme electron transfer mechanism with ˙O2−, 1O2, and h+ as the primary active species and Ag clusters as the electron transfer medium was proposed by combining the radical quenching experiments and the electron spin resonance (ESR) test. In this work, a prospective method for improving the photocatalytic efficiency of oxide semiconductor photocatalysts with a broad band gap was presented.