Phosphene-based Composite Two-dimensional Nanomaterials And Their Performance Of Photocatalytic Hydrogen Production

In recent years,with the sharp development of global industrialization,the demand for non-renewable fossil energy has increased sharply,causing global shortage of traditional energy sources.In addition,environmental pollution caused by burning the fossil energy has also become increasingly serious.Therefore,solving the problems of energy dificient and environmental are a necessary prerequisite for the harmonious development of mankind.Photocatalytic technology is a new technology that can efficiently converts solar energy into chemical energy.What is more,hydrogen energy is an ideal energy without pollution.Using solar energy to decompose water to produce hydrogen can fundamentally solve the problems of energy conjuncture and environmental pollution.Black phosphorus nanosheets（BP NSs）have attracted widespread attention in photocatalytic applications with their unique band-controllable structure and strong response in the visible to near-infrared range.In this paper,we regrade the BP NSs as the study object.Extensive preparation of black phosphorus nanosheets and improve hydrogen production performance of black phosphorus nanosheets by in situ loading cocatalysts on black phosphorus nanosheets are analyzed and evaluated.The main research contents of this article are as follows:1.Because the problems of complicated process,high cost,and difficulty in large-scale preparation of black phosphorus nanosheets,we will use red phosphorus as the raw material and ethylenediamine as the solvent to prepare the black phosphorus nanosheets by one-step solvothermal method.A series of experimental characterizations of the experiment proved that the prepared black phosphorus nanosheets have the properties of high purity,large size,and good crystallinity.The photocatalytic hydrogen production test have shown that the photocatalytic hydrogen production performance of the prepared black phosphorus nanosheets is better than red phosphorus and bulk black phosphorus.At the same time,cyclic experiments proved that the prepared black phosphorus nanosheets have good stability.Based on the characterization of electrochemical photoelectric properties,we also analyzed and discussed the photocatalytic hydrogen production mechanism of the prepared black phosphorus nanosheets.2.Based on the one-step preparation of BP NSs by the solvothermal method in Chapter1,we continue to load nickel phosphate nanoparticles in situ on the black phosphorus nanosheets by the solvent method to further improve its photocatalytic hydrogen production performance.X-ray diffraction（XRD）,transmission electron microscopy（TEM）,and X-ray photoelectron spectroscopy（XPS）tests confirmed that the BP/Ni₂P heterojunction was prepared successfully.The photocatalytic hydrogen production test proved that the photocatalytic performance of the prepared composite is far superior to BP NSs.We have further optimized the loading of Ni₂P nanoparticles and compared its photocatalytic hydrogen production performance with a simple mixture of BP+Ni₂P,which proves that in-situ loading of Ni₂P is more conducive to the formation of dense interfaces and electron transfer,thereby The photocatalytic hydrogen production performance of the hybrid is greatly ameliorated.3.We adopted a simple one-step photodeposition method to load transition metals（Co,Ni,etc.）on black phosphorus nanosheets in situ to prepare a BP/M（M=Co,Ni）heterojunction.Compared with solvothermal methods,this method has the advantages of short experimental period,simple,easy operation,green and no pollution.Test characterization proved that the transition metal supported on the black phosphorus nanosheets not only broadens its light absorption range,improves its solar light utilization efficiency,but also effectively alleviates the susceptibility of BP NSs to easy oxidation and improves its stability.The photocatalytic hydrogen production test proved that the prepared BP/M heterojunctions have excellent photocatalytic hydrogen production performance.Among them,the photocatalytic hydrogen production activity of the complex BP/Co heterojunction is about 160 times than that of BP NSs,and the photocatalytic hydrogen production activity of the complex BP/Ni heterojunction is 200 times than that of BP NSs.In addition,we also analyzed and discussed the photocatalytic hydrogen production mechanism of the prepared BP/M composite heterojunction by characterizing the electrochemical photoelectric properties.