Metallic 1T-LixMoS2 Cocatalyst Significantly Enhanced the Photocatalytic H2 Evolution over Cd0.5Zn0.5S Nanocrystals under Visible Light Irradiation

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• 作者：Hong Du ; Hong-Li Guo ; Ya-Nan Liu ; Xiao Xie ; Kuang Liang ; Xiao Zhou ; Xin Wang ; An-Wu Xu
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2016
• 出版时间：February 17, 2016
• 年：2016
• 卷：8
• 期：6
• 页码：4023-4030
• 全文大小：558K
• ISSN：1944-8252

文摘

In the present work, metallic 1T-Li_xMoS₂ is utilized as a novel cocatalyst for Cd_0.5Zn_0.5S photocatalyst. The obtained Li_xMoS₂/Cd_0.5Zn_0.5S hybrids show excellent photocatalytic performance for H₂ generation from aqueous solution containing Na₂S and Na₂SO₃ under splitting visible light illumination (λ ≥ 420 nm) without precious metal cocatalysts. It turns out that a certain amount of intercalating Li⁺ ions ultimately drives the transition of MoS₂ crystal from semiconductor triagonal phase (2H phase) to metallic phase (1T phase). The distinct properties of 1T-Li_xMoS₂ promote the efficient separation of photoexcited electrons and holes when used as cocatalyst for Cd_0.5Zn_0.5S photocatalyst. As compared to 2H-MoS₂ nanosheets only having edge active sites, photoinduced electrons not only transfer to the edge sites of 1T-Li_xMoS₂, but also to the plane active sites of 1T-Li_xMoS₂ nanosheets. The content of Li_xMoS₂ in hybrid photocatalysts influences the photocatalytic activity. The optimal 1T-Li_xMoS₂ (1.0 wt %)/Cd_0.5Zn_0.5S nanojunctions display the best activity for hydrogen production, achieving a hydrogen evolution rate of 769.9 μmol h^–1, with no use of noble metal loading, which is about 3.5 times higher than that of sole Cd_0.5Zn_0.5S, and 2 times higher than that of 2H-MoS₂ (1.0 wt %)/Cd_0.5Zn_0.5S samples. Our results demonstrate that Li⁺-intercalated MoS₂ nanosheets with high conductivity, high densities of active sites, low cost, and environmental friendliness are a prominent H₂ evolution cocatalyst that might substitute for noble metal for potential hydrogen energy applications.