Eco-friendly synthesis of core/shell ZnIn2S4/Ta3N5 heterojunction for strengthened dual-functional photocatalytic performance

Abstract

Reasonable design and fabrication of core/shell heterojunction has deemed as an efficient strategy to boost the transport and separation of photoinduced charge pairs in semiconductor-based photocatalytic system. Herein, a novel dual-functional ZnIn2S4/Ta3N5 (ZIS/TN) nanocomposite with intimate contacts was fabricated with a one-pot eco-friendly hydrothermal method. This core/shell heterojunction consisting of ZnIn2S4 nanosheet shell and Ta3N5 nanoparticle core is observed to possess the enhanced visible light harvesting capacity, increased specific surface areas, more high-speed charge nanochannels and accelerated charge transfer and separation. Thus, as prepared ZIS/TN nanocomposite displayed dramatically strengthened dual-functional photocatalytic performances of hydrogen production and tetracycline hydrochloride (TCH) photodegradation. As a result, the improved H2-production activity of 834.86 μmol g−1 h−1 was obtained by sample ZIS/TN-2, which is 6.07 times higher than that of pure ZnIn2S4 nanosheet. Moreover, the highest TCH photodegradation efficiency of 89.95% is achieved by the sample ZIS/TN-3, which is 1.90 and 11.01 times more than those of bare ZnIn2S4 and Ta3N5. In addition, the core/shell heterojunction exhibits super photostability and reusability due to the protection of external ZnIn2S4 layer from the photocorrosion of Ta3N5 core. Furthermore, the possible reaction mechanisms and the degradation intermediate products of TCH were also put forwarded in depth based on transient photocurrent response, active species tapping experiment, electronspin response (ESR) technique and HPLC-MS method. This work could stimulate an innovative vision in constructing dual-functional Ta3N5-based core/shell heterostructure with wonderful photocatalytic H2 evolution and antibiotic pollutant photodegradation activities.