| Nowadays,environmental pollution,energy exhaustion and other problems are becoming more and more serious.Semiconductor photocatalysis technology can effectively use solar energy to degrade pollutants.At the same time,photocatalytic fuel cell（PFC）prepared with semiconductor photocatalysis materials as photoelectric electrodes can realize the conversion of electrical energy while degrading pollutants.In this paper,ferromagnetic photocatalytic material with negative magnetoresistance（MR）effect is selected to compound with metal,and the photocatalytic activity of the system is further improved by increasing the specific surface area and external magnetic field,and then the composite photocatalyst material is applied in the field of PFC.The main research contents are as follows:First,the composite ferromagnetic photocatalytic material ZnFe2O4/Ag was prepared by hydrothermal synthesis technology and photoreduction technology.The energy band bending at the contact interface between ZnFe2O4 and Ag is beneficial to the efficient separation and transport of photogenerated carriers.In order to further regulate the photocatalytic performance,ZnFe2O4/Ag was deposited on silicon（Si）substrate with columnar morphology to prepare columnar Si/ZnFe2O4/Ag photocatalytic material.Columnar Si substrate has a large electrochemically active surface area,which can provide more reactive sites,so as to improve the photocatalytic performance.In addition,using the negative MR effect of ZnFe2O4/Ag,the separation and transport of photogenerated carriers are optimized through an external magnetic field,which further improved the photocatalytic performance of the sample.When no magnetic field was applied,the photocurrent density of columnar Si/ZnFe2O4/Ag is 0.621 m A/cm2,which is much higher than that of planar Si/ZnFe2O4/Ag（0.090 m A/cm2）.When a magnetic field of 1 k Oe was applied,the photocurrent density of columnar Si/ZnFe2O4/Ag increased to 1.315 m A/cm2.The energy band study,magnetic test and I-V test show that the interface structure formed by the composite of Si,ZnFe2O4 and Ag makes the composite photocatalyst material have greater MR.When the magnetic field was applied,the internal resistance of the material will change,allowing more photogenerated carriers to separate and transport through the interface in a unit time,thereby improving the overall photocatalytic performance.Second,ZnFe2O4/Ag ferromagnetic photocatalyst materials were applied in the field of PFC.ZnFe2O4/Ag was deposited on waterproof and breathable film as air breathing photocathode,and then a portable bipolar PFC was prepared by hot-melt film encapsulation.The PFC uses the semiconductor photocatalytic material as the photocathode,which replaces the precious metal material used in the traditional PFC cathode,which effectively reduces the production cost of PFC.In addition,the photoelectrode and fuel were encapsulated by hot-melt film,which effectively simplifies the structure of PFC,and can degrade pollutants and generate electric energy under light without the assistance of other equipment.In this bipolar PFC,the FTO/TiO2 seed layer/TiO2 nanorods prepared by hydrothermal method were used as the photoanode.First,the photoelectric conversion and photodegradation properties of the photoanode were studied.Then the overall output performance of PFC was studied.Due to the use of ZnFe2O4/Ag ferromagnetic photocathode material,the output performance of PFC was further improved under the condition of external magnetic field.Subsequently,the effects of light intensity,fuel type and electrolyte concentration on the output performance of PFC were investigated.The results show that the PFC has good optical response characteristics and stability.In addition,with the increase of light intensity and fuel concentration,the output performance of PFC was also improved,but the output performance of PFC was slightly decreased when using complex organic compounds as fuel.The research in this paper provides a reference method for the development of efficient photocatalysts and the improvement of existing photocatalysts.At the same time,the use of ferromagnetic semiconductor photocatalyst materials to replace precious metal materials as the photocathode of PFC can effectively reduce the preparation cost of PFC,and further improves the performance of PFC by adding magnetic field.PFC with cathode self-breathing structure is encapsulated by hot melt film,which is simple in structure and does not need other complicated external equipment.It can complete the degradation of pollutants and the conversion of electric energy only by lighting,providing a reference direction for the improvement of PFC. |
PDF Full Text Request