Synergistic effects of phosphorus doping and radial pores in WSe2/C microspheres for enhanced room-temperature NO2 sensing

Abstract

Room-temperature gas sensors 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 a precursor, in situ P-doping and the construction of a 3D mesoporous structure are simultaneously achieved. Similarly, other Si/P-doped mesoporous TMD (e.g. P-MoSe₂, Si-WSe₂, and Si-MoSe₂) composite microspheres have been prepared by using other polyoxometalate (POM) clusters as inorganic precursors. Such materials feature 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 an enhanced orbital hybridization effect. This work provides a new pathway for developing high-performance TMD-based gas sensors.