| Black phosphorus（BP）has the advantages of adjustable band gap related to the number of layers,in-plane anisotropy,high carrier mobility,good conductivity,large specific surface area,and rich photocatalytic active sites,and is a star material in the field of photocatalysis.However,the shortcomings of small layer of black phosphorus surface are easy to oxidize,photogen erated electron-hole easy recombination,cumbersome preparation process and high price limit its use in photodegradation and hydrogen evolution.In order to improve the disadvantage of black phosphorus easy oxidation,black phosphorus was grown in situ fro m red phosphorus（RP）powder by one-step solvothermal method.Due to the incomplete conversion of red phosphorus,a black phosphorus red phosphorus heterojunction（BP/RP）material was obtained.It not only takes advantage of the advantages of black phosphorus,but also reduces the self-oxidation of black phosphorus,bypasses the cumbersome step of"top-down"preparation of black phosphorus,and obtains the target catalyst in one step,which improves the economic benefits.Cadmium sulfide（Cd S）is a member of the metal sulfides.Its advantage is that the band gap matches the visible light,and it has a flat band potential that is more negative than the hydrogen redox potential for photocatalytic hydrogen evolution.The one-step solvothermal method is used to composite BP/RP with Cd S,which plays the role of co-catalyst in the photocatalytic hydrogen evolution process,improves the overall photoresponse ability,and accelerates the separation of photogenerated electron-hole pairs.The specific research content of this paper is as follows:（1）The photocatalytic degradation effect of BP/RP heterojunction materials prepared at different time and temperature was explored,and the photocatalytic degradation of methyl orange was evaluated through the photocatalytic d egradation experiment.In order to prove the successful preparation of BP/RP materials,the BP/RP heterojunction materials were confirmed by SEM,TEM,XRD,XPS,Raman and thermogravimetric characterization methods.By comparing the BP/RP materials prepared under various conditions,the materials with the best performance were selected.The photodegradation results of methyl orange showed that the BP/RP heterojunction material had far better degradation performance than RP.Among the BP/RP heterojunction mat erials prepared under different reaction temperature and reaction time,120 BP/RP composites degraded 97%of methyl orange solution within30 minutes.In contrast,RP degraded 8.5%of methyl orange solution in the same time.It can be proved that BP/RP heterojunction materials have excellent photocatalytic degradation performance.（2）On the basis of the successful preparation of BP/RP heterojunctions,the BP/RP-Cd S composites were synthesized by solvothermal method in one step.Since Cd S materials are pron e to photocorrosion under light,it may cause secondary pollution if applied in the photocatalytic degradation process.The photocatalytic hydrogen evolution experiments of the prepared Cd S nanoribbon and BP/RP-Cd S composites were carried out.It was found that the hydrogen evolution rate of BP/RP-Cd S composite increased to a certain extent.The hydrogen evolution rate of BP/RP-Cd S composite with 5%BP/RP was the highest,reaching 10.3 mmol·g-1·h-1,which was 2.21 times that of cadmium sulfide material.The hydrogen evolution rate(10.1 mmol·g-1·h-1)of BP/RP-Cd S composite containing 5%BP/RP can be achieved by supporting Pt cocatalyst on Cd S.This indicated that the effect of BP/RP co-catalyst was comparable to that of noble metal co-catalyst.The stability o f Cd S and BP/RP-Cd S composites was tested later,and the results showed that the addition of BP/RP to BP/RP-Cd S composites inhibited the decline of hydrogen evolution performance,showing good stability.This provides a possibility for the selection of cocatalyst in the subsequent Cd S photocatalytic hydrogen evolution,which can greatly reduce the catalyst cost. |
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