A Review on Electrospinning as Versatile Supports for Diverse Nanofibers and Their Applications in Environmental Sensing

Rapid industrialization is accompanied by the deterioration of the natural environment.The deepening crisis associated with the ecological environment has garnered widespread attention toward strengthening environmental monitoring and protection.Environmental sensors are one of the key technologies for environmental monitoring,ultimately enabling environmental protection.In recent decades,micro/nanomaterials have been widely studied and applied in environmental sensing owing to their unique dimensional properties.Electrospinning has been developed and adopted as a facile,quick,and effective technology to produce continuous micro-and nanofiber materials.The technology has advanced rapidly and become one of the hotspots in the field of nanomaterials research.Environmental sensors made from electrospun nanofibers possess many advantages,such as having a porous structure and high specific surface area,which effectively improve their performance in environmental sensing.Furthermore,by introducing functional nanomaterials(carbon nanotubes,metal oxides,conjugated polymers,etc.)into electrospun fibers,synergistic effects between different materials can be utilized to improve the catalytic activity and sensitivity of the sensors.In this review,we aimed to outline the progress of research over the past decade on electrospinning nanofibers with different morphologies and functional characteristics in environmental sensors.

Honeycomb-like g-C_(3)N_(4)/CeO_(2)-x nanosheets obtained via one step hydrothermal-roasting for efficient and stable Cr(Ⅵ) photo-reduction

Graphitic carbon nitride(g-C_(3)N_(4))-based materials are regarded as one of the most potential photocatalysts for utilizing solar energy.In this work,we reported a facile one step in-situ hydrothermal-roasting method for preparing honeycomb-like g-C_(3)N_(4)/CeO_(2) nanosheets with abundant oxygen vacancies(g-C_(3)N_(4)/CeO_(2)-x).The hydrothermal-roasting and incomplete-sealed state can(i)generate an in-situ reducing atmosphere(CO,N2,NH3) to tune the concentration of oxygen vacancies in CeO_(2);(ii) beneficial to prevent continuous growth of g-C_(3)N_(4) and results in honeycomb-like g-C_(3)N_(4)/CeO_(2)-x hybrid nanosheets.What is more,the g-C_(3)N_(4)/CeO_(2)-x photocatalyst exhibited extended photoresponse range,increased specific surface area and obviously enhanced separation efficiency of photogenerated electron-hole pairs.As a proof-of-concept application,the optimized g-C_(3)N_(4)/CeO_(2)-xnanosheets could achieve 98% removal efficiency for Cr(Ⅵ) under visible light irradiation(λ≥420 nm)within 2.5 h,which is significantly better than those of pure g-C_(3)N_(4) and CeO_(2).This work provides a new idea for more rationally designing and constructing g-C_(3)N_(4)-based catalysts for efficient extended photochemical application.