Tio2/Ti3c2tx Gel Microsphere for Efficient Photocatalytic Degradation of Organic Pollutant with Excellent Recycling Stability

Improving the recycling stability of photocatalysts is of great significance in practical applications. Herein, the in-situ prepared TiO2/Ti3C2Tx (TOTC) heterojunction is embedded in gel microsphere (GMS) as a recyclable photocatalyst TOTC@GMS for efficient photocatalytic degradation of Congo red (CR). The experimental results show that the removal rate can reach up to 99 % in 120 min without any co-catalysts (precious metals) or sacrificial reagents. The GMS can be recycled after rinsing in deionized water for only 2 min, and the removal rate can still maintain over 90 % even after 25 cycles. Besides, we also achieve a removal rate of 90% for CR in real water samples as the TOTC@GMS is exposed to natural sunlight for 180 min. The degradation mechanism reveals that hydroxyl radicals (•OH) and superoxide radicals (•O2-) are the main reactive species that triggered the decolorization of CR via means of free radical scavenging and electron paramagnetic resonance (EPR) experiments. The degradation products are further proposed by high-performance liquid chromatography-mass spectrometry (LC-MS), and the degradation pathways of CR are deduced. Additionally, a phytotoxicity test is carried out to confirm the non-toxicity of the organic micromolecules generated after degradation. This work presents a practical strategy to improve the recycling stability of photocatalysts, which can effectively reduce the cost of wastewater treatment.