Research On High Pressure Preparation And Functional Application Of Phosphorus-based Layered Materials

Black phosphorus is a natural P-type direct band gap semiconductor,which is endowed with many unique physical and chemical properties due to its two-dimensional layered structure.It makes up for the lack of zero band gap of graphene,has better carrier mobility characteristics than transition metal chalcogenide compounds,and has shown very good application prospects in many fields such as energy storage,optoelectronics,and biomedicine.It is promising become a material that is most likely to go to practical application after graphene.However,the poor environmental stability of black phosphorus severely restricts its further development and application,and the commercial application of black phosphorus still has a long way to go.This thesis starts with a new type of two-dimensional layered material black phosphorus,based on high-temperature and high-pressure preparation technology,while exploring the application of black phosphorus and black phosphorus modification.It further expands to other black phosphorus-like phosphorus-based layered materials.It carefully discussed the application fields of energy storage conversion and high-frequency electromagnetic loss respectively,and analyzed the relationship between its microstructure and performance.The main research results are as follows:（1）Developed a flexible self-supporting black phosphorus-graphene Janus film,using highly conductive graphene as the current collector,heat dissipation layer,and shielding layer,while using black phosphorus as the energy storage layer and shielding layer.And because of the presence of graphene,ultra-thin self-supporting Janus membranes can be easily made.It can be made into a flexible electronic device that can integrate electromagnetic shielding,heat dissipation,and energy storage.This lays the foundation for the application of black phosphorus in flexible multifunctional wearable electronic devices.Based on the high density and good conductivity of the black phosphorus-graphene Janus film,it has shown good application prospects in the three fields of supercapacitors,electromagnetic shielding,and heat dissipation.This kind of device that can integrate multiple functions will better meet people’s needs.（2）However,due to the poor environmental stability of black phosphorus,its further development and application are severely restricted,especially in the field of electrocatalysis.Here,we have synthesized sulfur-doped black phosphorus crystals using high-temperature and high-pressure preparation technology.This not only effectively alleviates the degradation of black phosphorus,but also the doping of sulfur element can effectively reduce the reaction barrier of black phosphorus,increase the active sites and charge transfer speed of black phosphorus nanosheets,thereby improving its oxygen evolution catalytic performance.The reaction mechanism of black phosphorus in oxygen evolution catalysis is explained through a combination of experiment and theoretical calculation.（3）Although the research on the modification of black phosphorus has made some progress,there is still a long way to go before practical application.The development of a new type of black phosphorus-like phosphorus-based layered material is also another good idea.We introduced indium,a metal element of the IIIA main group,into black phosphorus,and found that phosphorus and indium easily form a compound InP₃.Here,we synthesized high-purity InP₃ crystals through high-temperature and high-pressure directional growth technology,and further introduced a porous structure into the layered structure by controlling the cooling rate,and used it as an electrode material in a flexible all-solid supercapacitor.The experimental results show that InP₃ has excellent electrochemical energy storage performance,such as ultra-high power density,high energy density,high volume specific capacitance,and has good stretchability,flexibility and cycle stability.It has shown great potential in the field of energy storage.（4）Because GeP₅ has ultra-high electrical conductivity,it is more representative in layered metallic phosphides.And based on our research group has successfully applied GeP₅ nanosheets to supercapacitors with sandwich structure,but in terms of device structure and performance,it is not enough to meet people’s demand for high-performance wearable miniature energy storage devices.Therefore,we have grown in situ only a few nanometers of Ru O₂ nanoparticles on the highly conductive GeP₅ nanosheets to achieve the synergistic effect of the electric double layer and the pseudocapacitance,and use mask-assisted techniques to obtain high-resolution planar cross electrodes.By optimizing the microsupercapacitor device,a high-performance flexible wearable energy storage device with ultra-long cycle stability is prepared.（5）The metallic layered phosphides InP₃ and GeP₅ have good electrical conductivity,and InP₃ can be synthesized by controlling the cooling rate to introduce a porous structure in the layered material during high pressure synthesis,and GeP₅ can also introduce a suitable pore structure by controlling the annealing temperature.For this two-dimensional nanomaterial,it not only has good electrical conductivity,but also has a large specific surface area,which is very suitable for the field of electromagnetic wave absorption.Excelent electrical conductivity can cause strong dielectric loss of electromagnetic waves in the material.The introduction of the hole structure not only helps to construct light-weight absorbing materials,but also enhances the multi-level reflection loss of electromagnetic waves,thereby consuming electromagnetic wave energy to achieve good electromagnetic waves absorption effect.