Microwave-assisted synthesis of RuTe2/black TiO2 photocatalyst for enhanced diclofenac degradation: Performance, mechanistic investigation and intermediates analysis

Abstract

• The crystallized RuTe 2 acted as a cocatalyst for photocatalysis was reported for the first time. • 0.5% RuTe 2 /B-TiO 2 achieved 95.2% DCF degradation efficiency, which was 1.2 times higher than that of pure B-TiO 2 . • The intermediates for the photodegradation of DCF were detected and removal pathways was rationalized. Seeking active and low-cost cocatalysts is a vital task for solving the sluggish kinetics of photocatalysis process in environmental management. Herein, we report a novel and high-efficiency crystallized RuTe 2 cocatalyst, and loaded it onto black TiO 2 to form photocatalytic heterostructure (denoted as RuTe 2 /B-TiO 2 ) for diclofenac (DCF) degradation. To the best of our knowledge, the RuTe 2 as a cocatalyst for photocatalysis based on swift electron capture has not been documented yet. The degradation efficiency of DCF over 0.5% RuTe 2 /B-TiO 2 reached 95.2% for 120 min, which is 1.2 times higher than that of pure B-TiO 2 . In addition, the effects of different calcination temperatures, catalyst amounts, DCF concentrations and solution pH of the as-prepared catalysts were also investigated in depth. Spectroscopy/electrochemistry showed that 0.5% RuTe 2 /B-TiO 2 exhibited a narrower band gap, more active sites and better electrical conductivity than pure B-TiO 2 . Experiments with trapping agents have shown that O 2 – was the main active substance under irradiation. Furthermore, intermediates for the photodegradation of DCF were detected by liquid chromatography mass system (LC-MS) and density functional theory (DFT) calculations. Finally, the degradation pathway was rationalized and a possible photocatalytic mechanism for 0.5% RuTe 2 /B-TiO 2 was proposed.