摘要
Photo-corrosion is one of the major obstacles for CdS application in wet chemical fields, and atomic layer deposition （ALD） has been proposed as an effective way to suppress the corrosion. Here, prior to ALD coating, CdS, one facilely corrosive photocatalyst, was synthesized via hydrothermal synthesis to access the fundamental corrosion mechanism and the according corrosive sites. X-ray photoelectron spectros- copy （XPS） and X-ray diffraction （XRD） demonstrated that the failure of catalytic decomposition of methylene blue originated from the formation of soluble CdSO4 by oxidizing S2 of as-prepared CdS. High resolu- tion transmission electron microscopy （HRTEM） further identified the active sites in the V-shaped regions ofCdS nanoparticles, confirmed by the simulated electric field distribution. To rationally coat oxides on CdS, the right candidates and their thicknesses have been considered by our tunneling model with trans- fer matrix method based on quantum mechanism, upon which the thickness of protective layer should be less than 0.5 nm to maintain a high tunneling probability, and thus one cycle of ALD TiO2 or AbO3 was proposed to passivate the CdS powder to balance the carrier transportation and corrosion suppres- sion. Based on HRTEM results, we found that the active V-shaped region was covered by ALD oxides （TiO2 or AbO3）. For each case, no soluble CdSO4 has been found before and after photocatalytic reactions based XPS measurements. Importantly, we noticed that with the passivation of one cycle of ALD, the catalyst＇s lifetime was elongated up to 〉14 times higher than that of the as-prepared CdS.
Photo-corrosion is one of the major obstacles for CdS application in wet chemical fields, and atomic layer deposition （ALD） has been proposed as an effective way to suppress the corrosion. Here, prior to ALD coating, CdS, one facilely corrosive photocatalyst, was synthesized via hydrothermal synthesis to access the fundamental corrosion mechanism and the according corrosive sites. X-ray photoelectron spectros- copy （XPS） and X-ray diffraction （XRD） demonstrated that the failure of catalytic decomposition of methylene blue originated from the formation of soluble CdSO4 by oxidizing S2 of as-prepared CdS. High resolu- tion transmission electron microscopy （HRTEM） further identified the active sites in the V-shaped regions ofCdS nanoparticles, confirmed by the simulated electric field distribution. To rationally coat oxides on CdS, the right candidates and their thicknesses have been considered by our tunneling model with trans- fer matrix method based on quantum mechanism, upon which the thickness of protective layer should be less than 0.5 nm to maintain a high tunneling probability, and thus one cycle of ALD TiO2 or AbO3 was proposed to passivate the CdS powder to balance the carrier transportation and corrosion suppres- sion. Based on HRTEM results, we found that the active V-shaped region was covered by ALD oxides （TiO2 or AbO3）. For each case, no soluble CdSO4 has been found before and after photocatalytic reactions based XPS measurements. Importantly, we noticed that with the passivation of one cycle of ALD, the catalyst＇s lifetime was elongated up to 〉14 times higher than that of the as-prepared CdS.
基金
supported by the National Natural Science Foundation of China(Nos.11304161,11104148,21573117,51171082,11404172 and 61322508)
the 1000 Youth Talents Plan
the Tianjin Natural Science Foundation(Nos.13JCYBJC41100 and 14JCZDJC37700)
the National Basic Research Program of China(973 Program,Nos.2014CB931703 and 2013CB328701)
the Fundamental Research Funds for the Central Universities
