Zn1鈥?i>xCdxS Solid Solutions with Controlled Bandgap and Enhanced Visible-Light Photocatalytic H2-Production Activity

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• 作者：Qin Li ; Huan Meng ; Peng Zhou ; Yingqiu Zheng ; Juan Wang ; Jiaguo Yu ; JianRu Gong
• 刊名：ACS Catalysis
• 出版年：2013
• 出版时间：May 3, 2013
• 年：2013
• 卷：3
• 期：5
• 页码：882-889
• 全文大小：473K
• 年卷期：v.3,no.5(May 3, 2013)
• ISSN：2155-5435

文摘

Photocatalytic hydrogen (H₂) production from water splitting under visible-light irradiation is considered to be an attractive way to solve the increasing global energy crises in modern life. In this study, highly efficient photocatalytic H₂ production without the assistant of a cocatalyst was achieved using Zn1_1鈥?i>xCd_xS solid solutions as the visible-light-driven photocatalysts and a mixed Na₂S and Na₂SO₃ aqueous solution as the sacrificial reagent. The Zn_1鈥?i>xCd_xS samples were prepared by a simple zinc鈥揷admium鈥搕hiourea (Zn鈥揅d鈥揟u) complex thermolysis method using thiourea, zinc acetate (Zn(Ac)₂), and cadmium acetate (Cd(Ac)₂) as the precursors. The obtained Zn_1鈥?i>xCd_xS solid solutions feature a small crystallite size and precisely controllable band structure, which are beneficial for the photocatalysis. When the Zn/Cd molar ratio is 1:1, the prepared Zn_0.5Cd_0.5S sample exhibits the highest H₂-production rate of 7.42 mmol路h^鈥?路g^鈥?, exceeding that of the pure CdS and ZnS samples by more than 24 and 54 times, respectively, and even much higher than that of the optimal Pt-loaded CdS. This high photocatalytic H₂-production activity is attributed predominantly to enough visible-light absorption capacity and suitable conduction band potential of the Zn_0.5Cd_0.5S solid solution, which is further evidenced from the related theory calculations on the band structures of the Zn_1鈥?i>xCd_xS solid solutions. Moreover, the calculation on the Mulliken populations of Zn, Cd, and S atoms for the first time provides new insight into the deep understanding of the chemical shifts of element binding energies for the Zn_1鈥?i>xCd_xS solid solutions and the designing of new ternary photocatalytic materials.

Keywords:

Zn_1鈭?i>xCd_xS solid solution; thermolysis; theory calculation; visible light; hydrogen production