Amorphous molybdenum sulfide as highly efficient electron-cocatalyst for enhanced photocatalytic H-2 evolution
Amorphous molybdenum sulfide as highly efficient electron-cocatalyst for enhanced photocatalytic H-2 evolution
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无定形硫化钼作为高效电子助催化剂增强光催化 H-2 析出
DOI：
10.1016/j.apcatb.2016.04.028
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
Yu Jiaguo
中科院分区：
文献类型：
--
作者：
Yu Huogen;Xiao Pian;Wang Ping;Yu Jiaguo
开发新型、高性能的不含贵金属元素的电子助催化剂对光催化析氢反应具有重要意义。硫化钼是此类电子助催化剂的理想候选者之一，但其目前的性能受到不饱和S原子活性位稀缺的内在限制。采用吸附-原位转化法将非晶态MoSx（a-MoSx）纳米粒子直接固定在g-C3 N4表面，以提高其光催化放氢活性。结果表明，与晶态硫化钼（c-MoS_2）相比，a-MoS_x催化剂由于其高度不规则的排列结构，明显表现出更多的不饱和活性S原子.光催化实验结果表明，负载a-MoSx助催化剂可明显提高g-C3 N4光催化剂的析氢活性，其析氢活性明显高于未改性g-C3 N4和c-MoS 2/g-C3 N4。更重要的是，除了g-C3 N4之外，非晶态MoSx还可以作为有效的电子助催化剂，大大提高传统析氢材料如TiO 2（典型的紫外光光催化剂）和CdS（典型的可见光催化剂）的光催化性能。在此基础上，提出了非晶态MoSx光催化析氢活性提高的电子助催化机理，即非晶态MoSx能提供更多的不饱和活性S原子作为有效的活性位，快速捕获溶液中的质子，促进光生电子直接还原H+生成H2.非晶态MoSx助催化剂具有成本低、效率高等优点，在开发应用于各个领域的高性能光催化材料方面具有很大的潜力。
Exploiting novel and high-performance electron-cocatalysts without noble metallic element is of great significance for photocatalytic H2-evolution reaction. Molybdenum sulfide is one of the promising candidates of such electron-cocatalysts, but its present performance is intrinsically restrained by the scarce active sites of unsaturated S atoms. In this study, amorphous MoSx(a-MoSx) nanoparticles were directly anchored on the g-C3N4surface by an adsorption-in situ transformation method with the aim of improving photocatalytic H2-evolution activity. It was found that compared with the crystalline molybdenum sulfide (c-MoS2), the a-MoSxcocatalyst clearly exhibited more unsaturated active S atoms due to its highly irregular arrangement structure. Photocatalytic experimental results suggested that the H2-evolution activity of g-C3N4photocatalyst could be obviously improved by loading a-MoSxcocatalyst, which is obviously higher than that of unmodified g-C3N4and c-MoS2/g-C3N4. More importantly, in addition to the g-C3N4, the amorphous MoSxcould also work as the efficient electron cocatalyst to greatly enhance the photocatalytic performance of conventional H2-evolution materials such as TiO2(a typical UV-light photocatalyst) and CdS (a typical Vis-light photocatalyst). On the basis of the present results, an electron-cocatalyst mechanism of amorphous MoSxwas proposed to account for the improved photocatalytic H2-evolution activity, namely, the amorphous MoSxcan provide more unsaturated active S atoms as the efficient active sites to rapidly capture protons from solution, and then promote the direct reduction of H+to H2by photogenerated electrons. Considering its low cost and high efficiency, the amorphous MoSxcocatalyst would have great potential for the development of high-performance photocatalytic materials used in various fields.