Study On Photocatalytic Performance Of Black Phosphorus Composite Semiconductor Materials

In the past few decades,various harmful chemicals have caused serious pollution to water,air and soil.Environmental treatment technologies that can effectively treat these pollutants have become an urgent need.Semiconductor photocatalytic technology has entered people’s field of vision due to its green,efficient and stable characteristics,and has been deeply studied by scientific researchers.Black phosphorus(BP),as an emerging two-dimensional material,has an adjustable direct band gap(E_g=0.3 e V for bulk BP,versus E_g=2.0 e V for monolayer BP),which shows that BP has a wide range of light absorption from ultraviolet to visible and even to near infrared.In addition,BP also has unique characteristics such as ultra-high charge mobility,high light absorption coefficient,large specific surface area and anisotropic structure,making it a potential photocatalytic material.Therefore,exploring the application of BP in photocatalysis has important research value.The main research contents of this article are as follows:(1)Bulk BP was prepared by chemical vapor transport method,and black phosphorus was exfoliated into BP nanosheets(BPNs)in an organic solvent.Zn O was combined with BPNs by co-precipitation to form BPNs-Zn O nanohybrid.Various characterization tests have proved the effective construction of BPNs and Zn O heterojunctions.The presence of BPNs broadens the Zn O light absorption range and carrier transport path,and suppresses carrier recombination.During the 60-minute photocatalytic degradation process,the degradation rates of BPNs-Zn O nanohybrid to methylene blue(MB)and ciprofloxacin(CIP)were 96.1%and 98.2%,respectively,much higher than other comparative samples.The photocatalytic degradation mechanism of the BPNs-Zn O nanohybrid was studied and a theoretical explanation was proposed.(2)By adding the polymer electrolyte PDDA to the aqueous solution,BP is stably exfoliated into BPNs in the aqueous solution.The BPNs-Bi OBr nanocomposite was prepared by co-precipitation method.The BPNs-Bi OBr nanocomposite was prepared by co-precipitation method.The degradation efficiency of the BPNs-Bi OBr nanocomposite with the best degradation effect on methyl orange(MO)and CIP was 98.1%and 98.2%,respectively,much higher than Bi OBr and BPNs.Repeated degradation experiments prove that BPNs-Bi OBr nanocomposite is an efficient and stable photocatalyst.Various characterization testing methods have proved the successful formation of Bi OBr and BPNs heterostructures,leading to efficient carrier separation and transmission,which greatly improves the photocatalytic performance.By studying the photocatalytic mechanism,we proposed that the BPNs-Bi OBr nanocomposite constitutes a type-I band gap configuration.(3)The exfoliated black phosphorus and Co Fe-LDHs were placed in different organic solvents,respectively.Using the electrical differences between the two materials,the BPNs/Co Fe-LDHs nanohybrids were successfully constructed through electrostatic self-assembly method.Relevant characterization proves that a good heterogeneous contact is formed between Co Fe-LDHs and BPNs.The results of photocatalysis experiments showed that BPNs/Co Fe-LDHs nanohybrids had a removal rate of 95.2%for MB,while Co Fe-LDHs only reached63.7%,and BPNs had almost no obvious degradation effect.Repeated degradation experiments proved that BPNs/Co Fe-LDHs nano-hybrid is a stable photocatalyst.