【Frontiers in HaiChuan Chemical Technology】The Institute of Metal Research, Chinese Academy of Sciences, has successfully developed floating titanium dioxide to make waste plastic treatment more efficient

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On May 7, reporters learned from the Institute of Metal Research, Chinese Academy of Sciences, that researchers from this institute and other institutions have successfully developed a floating titanium dioxide material. This material can decompose plastics when exposed to light; without the need for pretreatment of plastics with acid or alkali solutions, its efficiency in breaking down common plastics such as plastic bags and plastic wrap is dozens to hundreds of times higher than that of traditional materials, setting a new record for plastic decomposition efficiency under neutral conditions. More importantly, 40% of the products obtained from the decomposition of waste plastics using this material is ethanol. The relevant findings were published in Nature Communications. Plastics are widely used in various fields such as packaging, medicine, and aerospace. However, the total amount of plastic waste worldwide has now reached 6.4 billion tons, posing a serious threat to environmental safety and human health. How to deal with this waste plastic has become a global challenge. Against this background, photocatalytic plastic decomposition technology has attracted attention. This technology can convert waste plastics into useful chemical raw materials by using light to irradiate semiconductor photocatalytic materials. Titanium dioxide is a commonly used semiconductor photocatalytic material that can generate hydroxyl radicals capable of decomposing plastics under light exposure. These hydroxyl radicals act like “molecular scissors,” capable of cutting the molecular chains of plastics. “However, hydroxyl radicals have significant drawbacks: their lifetime is only on the order of one billionth of a second, and their effective range is only 10–100 nanometers. Short-lived free radicals have difficulty reaching the surface of plastic products effectively. ”Liu Gang, the corresponding author of the paper and a researcher at the Institute of Metal Research, Chinese Academy of Sciences, said that as a result, people have to first treat the plastic with strong acid or strong alkali solutions for corrosion; however, this pretreatment step accounts for 85% of the total cost of the degradation process. In this study, researchers broke away from conventional approaches by coating titanium dioxide with a \"waterproof armor,\" enabling it to float on the water’s surface. Compared to traditional titanium dioxide, floating titanium dioxide has two new functions: one is to enable direct contact between sunlight, oxygen, photocatalytic materials, and plastic, thereby breaking through the barrier that previously existed between photocatalytic materials and plastic ； Secondly, superoxide radicals with a longer lifespan can be utilized; their lifetime is as long as 1 millisecond, allowing them to fully break the carbon chains of plastic molecules.