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ZnO-dotted porous ZnS cluster microspheres for high efficient, Pt-free photocatalytic hydrogen evolution.

Wu A, Jing L, Wang J, Qu Y, Xie Y, Jiang B, Tian C, Fu H - Sci Rep (2015)

Bottom Line: Importantly, a series of the experiments and theoretical calculation demonstrate that the dotting of ZnO not only makes the photo-generated electrons/hole separate efficiently, but also results in the formation of the active catalytic sites for PHE.As a result, the PCMS-1 shows the promising activity up to 367 μmol h(-1) under Pt-free condition.The easy synthesis process, low preparation cost of the PCMS makes their large potential for Pt-free PHE.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education of the People's Republic of China, Heilongjiang University, Harbin 150080 (P. R. China).

ABSTRACT
The Pt-free photocatalytic hydrogen evolution (PHE) has been the focus in the photocatalysis field. Here, the ZnO-dotted porous ZnS cluster microsphere (PCMS) is designed for high efficient, Pt-free PHE. The PCMS is designed through an easy "controlling competitive reaction" strategy by selecting the thiourea as S(2-) source and Zn(Ac)₂·2H₂O as Zn source in ethylene glycol medium. Under suitable conditions, one of the PCMS, named PCMS-1, with high SBET specific area of 194 m(2)g(-1), microsphere size of 100 nm and grain size of 3 nm can be obtained. The formation of PCMS is verified by TEM, XAES, XPS, Raman and IR methods. Importantly, a series of the experiments and theoretical calculation demonstrate that the dotting of ZnO not only makes the photo-generated electrons/hole separate efficiently, but also results in the formation of the active catalytic sites for PHE. As a result, the PCMS-1 shows the promising activity up to 367 μmol h(-1) under Pt-free condition. The PHE activity has no obvious change after addition 1 wt.% Pt, implying the presence of active catalytic sites for hydrogen evolution in the PCMS-1. The easy synthesis process, low preparation cost of the PCMS makes their large potential for Pt-free PHE.

No MeSH data available.


(a) The PHE activity of PCMS, C-ZnS and ZnO/ZnS; (b) the recycled PHE activity of PCMS-1. The ZnO/ZnS is prepared according to the Ref. 25.
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f4: (a) The PHE activity of PCMS, C-ZnS and ZnO/ZnS; (b) the recycled PHE activity of PCMS-1. The ZnO/ZnS is prepared according to the Ref. 25.

Mentions: The promising characteristics of PCMS, including the uniform dotting of ZnO on ZnS, the porous structure and small crystallite size are favorable for its application in PHE. The PHE activity of PCMS was evaluated under UV-light irradiation without using Pt cocatalyst, and the results are shown in Figure 4a. We can see that all PCMS samples show obvious activity and the PCMS-1 sample gives the highest one. The H2-production rate is about 367 μmol h−1, 188 μmol h−1, 312 μmol h−1 and 234 μmol h−1 for PCMS-1, PCMS-0.5, PCMS-2.5 and PCMS-5, respectively (Figure 4a). The activity of PCMS samples is higher than that of some Pt-free photocatalysts, for example, ternary TiO2-MoS2/graphene (165.3 μmol h−1)17. However, the commercial ZnS (C-ZnS) only show neglectable PHE activity (17 μmol h−1) in identical conditions. As a control, we have also synthesized the rod-like ZnO/ZnS rods according to the Ref. 25. The PHE activity of the ZnO/ZnS rods is about 110 μmol h−1. The activity of PCMS-1 is about 3 times higher than that of the ZnO/ZnS rods. The lower activity of ZnO/ZnS rods should be relative with the larger size of ZnO and ZnS in the composites. The results indicate that the formation of the ZnO-dotted porous ZnS structure is favorable for promoting the PHE activity largely.


ZnO-dotted porous ZnS cluster microspheres for high efficient, Pt-free photocatalytic hydrogen evolution.

Wu A, Jing L, Wang J, Qu Y, Xie Y, Jiang B, Tian C, Fu H - Sci Rep (2015)

(a) The PHE activity of PCMS, C-ZnS and ZnO/ZnS; (b) the recycled PHE activity of PCMS-1. The ZnO/ZnS is prepared according to the Ref. 25.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4352920&req=5

f4: (a) The PHE activity of PCMS, C-ZnS and ZnO/ZnS; (b) the recycled PHE activity of PCMS-1. The ZnO/ZnS is prepared according to the Ref. 25.
Mentions: The promising characteristics of PCMS, including the uniform dotting of ZnO on ZnS, the porous structure and small crystallite size are favorable for its application in PHE. The PHE activity of PCMS was evaluated under UV-light irradiation without using Pt cocatalyst, and the results are shown in Figure 4a. We can see that all PCMS samples show obvious activity and the PCMS-1 sample gives the highest one. The H2-production rate is about 367 μmol h−1, 188 μmol h−1, 312 μmol h−1 and 234 μmol h−1 for PCMS-1, PCMS-0.5, PCMS-2.5 and PCMS-5, respectively (Figure 4a). The activity of PCMS samples is higher than that of some Pt-free photocatalysts, for example, ternary TiO2-MoS2/graphene (165.3 μmol h−1)17. However, the commercial ZnS (C-ZnS) only show neglectable PHE activity (17 μmol h−1) in identical conditions. As a control, we have also synthesized the rod-like ZnO/ZnS rods according to the Ref. 25. The PHE activity of the ZnO/ZnS rods is about 110 μmol h−1. The activity of PCMS-1 is about 3 times higher than that of the ZnO/ZnS rods. The lower activity of ZnO/ZnS rods should be relative with the larger size of ZnO and ZnS in the composites. The results indicate that the formation of the ZnO-dotted porous ZnS structure is favorable for promoting the PHE activity largely.

Bottom Line: Importantly, a series of the experiments and theoretical calculation demonstrate that the dotting of ZnO not only makes the photo-generated electrons/hole separate efficiently, but also results in the formation of the active catalytic sites for PHE.As a result, the PCMS-1 shows the promising activity up to 367 μmol h(-1) under Pt-free condition.The easy synthesis process, low preparation cost of the PCMS makes their large potential for Pt-free PHE.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education of the People's Republic of China, Heilongjiang University, Harbin 150080 (P. R. China).

ABSTRACT
The Pt-free photocatalytic hydrogen evolution (PHE) has been the focus in the photocatalysis field. Here, the ZnO-dotted porous ZnS cluster microsphere (PCMS) is designed for high efficient, Pt-free PHE. The PCMS is designed through an easy "controlling competitive reaction" strategy by selecting the thiourea as S(2-) source and Zn(Ac)₂·2H₂O as Zn source in ethylene glycol medium. Under suitable conditions, one of the PCMS, named PCMS-1, with high SBET specific area of 194 m(2)g(-1), microsphere size of 100 nm and grain size of 3 nm can be obtained. The formation of PCMS is verified by TEM, XAES, XPS, Raman and IR methods. Importantly, a series of the experiments and theoretical calculation demonstrate that the dotting of ZnO not only makes the photo-generated electrons/hole separate efficiently, but also results in the formation of the active catalytic sites for PHE. As a result, the PCMS-1 shows the promising activity up to 367 μmol h(-1) under Pt-free condition. The PHE activity has no obvious change after addition 1 wt.% Pt, implying the presence of active catalytic sites for hydrogen evolution in the PCMS-1. The easy synthesis process, low preparation cost of the PCMS makes their large potential for Pt-free PHE.

No MeSH data available.