| As an organic photocatalyst with semiconductor properties,carbon nitride(CN)has the advantages of cheap and easy to get,safe and non-toxic,suitable structure of the belt,and is a visible photocatalytic material with great application prospects.How to further promote CN to improve its photocatalytic performance is an urgent scientific problem.1.In this paper,a defective ultrathin mesoporous carbon nitride(DCN)photocatalytic agent is prepared by using the high temperature hydrogenation reduction method,and DCN has the characteristics of ultrathin,mesoporous,defects,and so on.By calcining at high temperature hydrogen to obtain the best defective concentration of DCN,the presence of surface defects to reduce the band gap from 2.64 e V to 2.42 e V,DCN visible light catalytic hydrogen production performance is 4 times that of ultrathin mesoporous carbon nitride(UCN),16 times that of BCN.This is due to the formation of defective structures to reduce the band gap,broaden the absorption range of sunlight,moderate defects also benefit the separation and transmission of photoactive charge,as well as ultrathin and inter pore structure to provide a large number of surf activity bits.We have further verified the type,location and concentration of defects in the catalyst structure through theoretical calculations.2.In order to further improve the utilization rate of sunlight,using nitrogen vacancy anchoring and ?-? interaction to load polydopamine nanoparticles on defective ultra-thin mesoporous carbon nitride nanosheets,synthesis of polydopamine/defective ultra-thin mesoporous carbon nitride(PDA/DCN)nanocomposite photocatalyst was synthesized.PDA/DCN composite photocatalyst is an efficient all-solar spectral UV-visible light-nearinfrared(UV-vis-NIR)optical-driven photocatalyst that rapidly photocatalysis hydrogen production.By regulating the load of the PDA and exploring the optimal photocatalytic performance ratio,PDA/DCN visible light catalytic hydrogen production performance is 2 times better than that of DCN due to the formation of a Z-type electron transfer mechanism between the two materials that allows for effective separation of photoelectric charges.And PDA has the ability of strong adsorption and extended spectral absorption,PDA can also produce the photothermal effect,improve reaction temperature,improve catalytic activity,thereby further improving the photocatalytic performance.3.In order to further improve performance,a complete photocatalytic system,hosted by PDA/DCN,uses low-temperature frozen light deposition to prepare the polydopamine/defective micro-thin median nitride carbon(Ag-PDA/DCN)nanoassemblies material for nano-silver loads.This material forms a heterogeneous structure at the interface between Ag-and PDA,and the load of metal Ag can act as a catalyst,using Ag nanoparticles to further promote the transmission and separation of photocarriers,thereby improving the separation efficiency of photoelectronic-cavity pairs.Ag-PDA/DCN photocatalytic hydrogen production performance is 6 times higher than that of PDA/DCN without the addition of a catalyst aid.This is due to the formation of Ag nanoparticles of the catalyst action and Ag's small size of high dispersion advantages,which can better promote the separation of photo-carriers,inhibit the electron-cavitation pair compound,and improve the utilization rate of visible light,thereby improving the performance of photocatalytic hydrogen production.The design of this new assembly provides new ideas for the development of photocatalytic assembly materials for solar energy conversion and has potential applications in the field of the environment. |
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