Study on Structural Stability of Black Phosphorus/Bismuth Oxysulfide/Tungsten Trioxide Heterojunction Based on XRD Measurement

X-ray diffraction is employed to characterize the black phosphorus/bismuth oxysulfide/tungsten trioxide heterojunction composites to explore the alterations in crystallite size and micro-strain. The sample is immersed in sodium sulfite and tested each week. The Scherrer formula and Williamson-Hall plots are used to explore the effect of black phosphorus on improving the stability of the bismuth oxysulfide/tungsten trioxide heterojunction. The results show that the structure of black phosphorus/bismuth oxysulfide/tungsten trioxide heterojunction has changed as follows. The value of crystallite size of tungsten trioxide decreases from 13.82 nm to 9.23 nm, then to 7.45 nm per week, while the value of compressive micro-strain of WO3 increases from -2.02×10−3 to -7.58×10−3, then to -8.93×10−3. It illustrates that the lattice constant of WO3 is compressed due to the lattice mismatch.