Recent Advancements on Photothermal Conversion and Antibacterial Applications over MXenes-Based Materials

The pernicious bacterial proliferation and emergence of super-resistant bacteria have already posed a great threat to public health,which drives researchers to develop antibiotic-free strategies to eradicate these fierce microbes.Although enormous achievements have already been achieved,it remains an arduous challenge to realize efficient sterilization to cut off the drug resistance generation.Recently,photothermal therapy(PTT)has emerged as a promising solution to efficiently damage the integrity of pathogenic bacteria based on hyperthermia beyond their tolerance.Until now,numerous photothermal agents have been studied for antimicrobial PTT.Among them,MXenes(a type of two-dimensional transition metal carbides or nitrides)are extensively investigated as one of the most promising candidates due to their high aspect ratio,atomic-thin thickness,excellent photothermal performance,low cytotoxicity,and ultrahigh dispersibility in aqueous systems.Besides,the enormous application scenarios using their antibacterial properties can be tailored via elaborated designs of MXenes-based materials.In this review,the synthetic approaches and textural properties of MXenes have been systematically presented first,and then the photothermal properties and sterilization mechanisms using MXenes-based materials are documented.Subsequently,recent progress in diverse fields making use of the photothermal and antibacterial performances of MXenes-based materials are well summarized to reveal the potential applications of these materials for various purposes,including in vitro and in vivo sterilization,solar water evaporation and purification,and flexible antibacterial fabrics.Last but not least,the current challenges and future perspectives are discussed to provide theoretical guidance for the fabrication of efficient antimicrobial systems using MXenes.

PtCu-SnO_(2)nanocomposites for ultrasensitive and rapid ultra-low formaldehyde sensing

SnO 2 nanospheres with diameters of 30∼50 nm and Pt x Cu 1-x bimetallic nanoparticles with sizes of approxi-mately 10 nm were synthesized via hydrothermal and solvothermal methods,respectively.The Pt x Cu 1-x bimetal-lic nanoparticles were impregnated on the surface of the SnO 2 spheres to form Pt x Cu 1-x-SnO 2 nanocomposites.By varying the atomic ratios between platinum(Pt)and copper(Cu),we found that Pt 0.75 Cu 0.25-SnO 2,with a large specific surface area of 89.21 m 2/g,enabled the selective and accurate detection of low-concentration formalde-hyde compared to other metal-deposited samples and pure SnO 2.The response value of Pt 0.75 Cu 0.25-SnO 2 to 500×10−9 formaldehyde was approximately 20 at an operating temperature of 160◦C with an extremely high-speed response(15 s).The porous structures with large specific surface areas,as well as the improved catalytic effects of Pt 0.75 Cu 0.25,comprehensively contributed to the enhanced sensing performance towards formaldehyde.