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.