Optimization of Intercalated 2D BiOCl Sheets into Bi2WO6 Flowers for Photocatalytic NH3 Production and Antibiotic Pollutant Degradation

Photocatalytic N-2 fixation is a complex reaction,therebyprompting researchers to design and analyze highly efficient materials.Herein, one-pot hydrothermal Bi2WO6-BiOCl(BW-BiOCl) heterojunctions were synthesized by varying themolar ratio of tungsten: chlorine precursor. Major morphological transformationsin BiOCl were observed wherein it turned from thick sheets & SIM;230nm in pure BiOCl to & SIM;30 nm in BW-BiOCl. This was accompaniedby extensive growth of {001} facets verified from X-ray diffraction(XRD) and field-emission scanning electron microscopy (FESEM) analyses.A p-n heterojunction was formed between Bi2WO6 and BiOCl evidenced via photoluminescence (PL), time-resolvedphotoluminescence (TRPL), photocurrent response, and electrochemicalimpedance spectroscopy (EIS) analyses. The formation of heterojunctionbetween Bi2WO6 and BiOCl led to the reductionof the work function in the BW-BiOCl 0.25 hybrid confirmedvia ultraviolet photoelectron spectroscopy (UPS) analysis. BW-BiOCl0.25 could produce ammonia up to 345.1 & mu;mol & BULL;L-1 & BULL;h(-1) owing to the formation of a robust heterojunctionwith an S-scheme carrier transport mechanism. Recycle tests resultedin no loss in N-2 reduction activities with post-catalyticanalysis, showcasing the high stability of the synthesized heterojunction.Novel performance was owed to its excellent chemisorption of N-2 gas on the heterojunction surface verified by N-2-temperature programmed desorption (TPD). BW-BiOCl 0.25 alsodisplayed a superior rate constant of 3.03 x 10(-2) min(-1) for 90 min CIP degradation time, higherthan pristine BiOCl and Bi2WO6. Post-photocatalyticFourier transform infrared (FTIR) spectroscopy of BW-BiOCl0.25 revealed the presence of C-H stretching peaks in the rangeof 2850-2960 cm(-1) due to adsorbed CIP andmethanol species in CIP degradation and N-2 fixation, respectively.This also confirmed the enhanced adsorption of reacting species ontothe heterojunction surface.

Automated summary

Photocatalytic N-2 fixation is a complex reaction, which requires the design and analysis of highly efficient materials. In this study, one-pot hydrothermal Bi2WO6-BiOCl heterojunctions were synthesized by adjusting the molar ratio of tungsten and chlorine precursor. The formation of a p-n heterojunction between Bi2WO6 and BiOCl resulted in a reduction of the work function and improved catalytic performance.