Synergistic Effects of Phosphorus Doping and Radial Pores in WSe2/C Microspheres for Enhanced Room-Temperature NO2 Sensing

Abstract

Room-temperature gas sensor based on two-dimensional (2D) transition metal dichalcogenides (TMDs) have been limited by insufficient gas adsorption capacity and restricted gas diffusion. Herein, a facile and general synthesis strategy is developed to fabricate mesoporous phosphorus-doped WSe2/carbon composite microspheres (mP-WSe2/C). Using mesoporous polydopamine as a template and phosphotungstic acid (H3PW12O40) as precursor, in-situ P-doping and the construction of a 3D mesoporous structure are simultaneously achieved. Similarly, other Si/P-doped mesoporous TMDs (e.g. P-MoSe2, Si-WSe2, Si-MoSe2) composite microspheres have been prepared by using other polyoxometalate (POMs) clusters as inorganic precursors. Such obtained material features high crystallinity, abundant defects, and fully accessible active sites.For instance, our mP-WSe2/C-based semiconductor sensor exhibits outstanding room-temperature NO2 sensing performance, including fast response/recovery (24 s/31 s), high response (27 % to 100 ppm), and excellent selectivity.Theoretical calculations confirm that P-doping enhances NO2 adsorption and electron transfer by enhanced orbital hybridization effect. This work provides a new pathway for developing high-performance TMDs-based gas sensors.