Study On Synergistic Photocatalytic Properties Of Modified Spinel Activated Persulfate

Antibiotics,dyes,and heavy metals,among other dangerous contaminants,have wreaked havoc on the ecosystem in recent years.Circulating into the aquatic environment causes severe pollution,which poses a major threat to human health and societal development.As the advantages of photocatalysis technique:safety,efficiency,and environmental friendliness,it has evolved into a novel and effective technology for addressing and resolving environmental degradation and energy shortages.Low quantum efficiency and low visible light activity are the two most pressing scientific issues in photocatalytic technology today.Hence,it is a vital key to devise an appropriate photocatalyst.Due to their unique photoelectric characteristics,cobalt-based spinel materials have been a research focus for cocatalyst and photocatalyst.Meantime,for the distinctiveness of its internal electronic structure,cobalt-based spinel materials is also suitable for the creation of an in-situ Fenton-like system to generate H₂O₂ and improve catalytic performance.Besides,it can also cooperate with peroxydisulfate（PDS）to achieve efficient catalytic degradation activity.Cobalt-based spinel nano photocatalyst is expected to degrade antibiotics and dyes,reduce heavy metals,and realize environmental remediation and energy reuse.1.Cu_1-xCo_2-yO_4-z with bimetallic defects was designed by temperature programmed reduction （TPR）,a simple reduction technology.The coexistence of metal defects leads to defect distortion and polarization effect,which greatly accelerates the separation of photogenerated carriers.By optimizing the band gap structure,Cu_1-xCo_2-yO_4-z generates H₂O₂(78μmol·g^-1·h^-1,without sacrificial agents and additives)to promote the production of·OH.The photodegradation of Cu_1-xCo_2-yO_4-z for methylene blue（MB）can reach more than 7.8 times that of bulk Cu Co₂O₄.At the same time,due to its high reduction activity, the reduction efficiency of Cr（Ⅵ）is improved by more than 8 times. Experimental data explain that the in-plane polarization electric field caused by defect effect will also rapidly separate and migrate carriers.In addition,Cu_1-xCo_2-yO_4-z can effectively stimulate PDS to produce highly active^·O₂^-and ¹O₂ to achieve efficient degradation of MB and sulfamethoxazole（SMX）.Cobalt-based spinel nano photocatalyst is expected to be used in the removal of antibiotics and heavy metals.It is an ideal photocatalytic nano material for environmental remediation and energy reuse.2.Based on the study of bimetallic defects effect of similar metals,a Fe_1-xCo_2-yO_4-z nano photocatalytic material with multi defect effect was designed.Fe_1-xCo_2-yO_4-z not only enhances its photocatalytic activity,but also activates PDS to exert excellent photocatalytic performance.The coexistence of metal defects leads to lattice distortion and orderly accumulation,which greatly accelerates the separation of photogenerated carriers.At the same time,the defect effect also optimizes the microstructure and makes it give better play to the migration of photogenerated carriers.By optimizing the band gap structure,Fe_1-xCo_{2- y}O_4-z generates the H₂O₂ effect(18.9μmol·g^-1·h^-1)to assist in promoting the production of ·OH.The photodegradation of methylene blue can reach more than 3 times that of Fe Co₂O₄. Experimental data confirm that the in-plane polarization electric field caused by defect effect will also rapidly separate and migrate carriers.On the other hand,the strong reduction characteristics induce Fe_1-xCo_2-yO_4-z to realize the high-efficiency photoreduction of Cr（Ⅵ）. Most importantly,Fe_1-xCo_2-yO_4-z can effectively stimulate PDS to produce highly active ¹O₂ to realize the efficient degradation of a variety of organic pollutants.3.Based on the study of the influence of stable valence metals on defect effect,a novel defective ZnCo_2-xO_4-y nano material was designed and synthesized.It can not only realize its own stable and high-efficiency photocatalytic activity,but also activates PDS to achieve outstanding photocatalytic quality.The interaction between Co defects and oxygen vacancies induces crystal plane optimization and assembly stacking,which greatly accelerates the separation of photogenerated carriers.On the one hand,ZnCo_2-xO_4-y can generate H₂O₂(10.9μmol·g^-1h^-1)by using the optimized band gap structure,which assists the production of·OH to improve the photodegradation activity of methylene blue.On the other hand,the strong reduction characteristics induce ZnCo_2-xO_4-y to use dissolved oxygen to produce^·O₂^-and ¹O₂ to achieve high-efficiency photoreduction of Cr（Ⅵ）. Experimental data show that the in-plane polarization electric field caused by multi defect effect will also rapidly separate and migrate carriers.