Ultra-sensitive triethylamine gas sensors based on polyoxometalate-assisted synthesis of ZnWO4/ZnO hetero-structured nanofibers

Abstract

One-dimensional hetero-structured nanofibers (NFs) have recently received great attention because of their rich architectures and potential applications in the field of gas sensors. Polyoxometalate (POM) is a unique nanosized transition metal-oxygen cluster used as a molecular platform to prepare metal oxide nanomaterials and accompanied by high negative charges that readily combine with various metal oxide precursors to form metal oxide complexes. Herein, with the assistance of POM, ZnWO 4 /ZnO hetero-structured NFs were prepared by combining facile electrospinning with thermal oxidation. Adjusting the molar ratio of POM (H 3 PW 12 O 40 ·xH 2 O, denoted as PW 12 ) and Zn(NO 3 ) 2 ·6H 2 O (denoted as Zn 2+ ) in the precursor solution, a series of ZnWO 4 /ZnO hetero-structured NFs were obtained. Compared with pure ZnO NFs, the optimized ZnWO 4 /ZnO hetero-structured NFs demonstrate more excellent sensing performance. A high relative response of 108.5 was achieved for 50 ppm triethylamine (TEA) and with a low detection limit about 150 ppb. Furthermore, the ZnWO 4 /ZnO hetero-structured NFs exhibited remarkable TEA selectivity and outstanding reproducibility. The enhanced sensing mechanism toward TEA could be attributed to n-n heterojunctions with the obvious barrier-control electron transfer effect at the interface between ZnWO 4 and ZnO. The one-dimensional ZnWO 4 /ZnO hetero-structured nanofibers were prepared with the assistance of polyoxometalate to realize the ultra-sensitive detection of triethylamine. • ZnWO 4 /ZnO hetero-structured nanofibers were prepared by an electrospinning method with the assistance of polyoxometalate. • As-prepared porous nanofibers exhibited an enhanced selectivity to triethylamine with excellent stability/repeatability. • The excellent sensing performance is mainly ascribed to porous structure and synergetic sensing effect of ZnWO 4 and ZnO.