### 构建NiS2/MoSe2 S型异质结高效光催化产氢

1. 1 北方民族大学化学与化学工程学院，宁夏太阳能化学转化技术重点实验室，国家民委化工技术基础重点实验室，银川 750021
2 银川能源学院机械与汽车工程系，银川 750100ng Liu, Xuqiang Hao, Haiqiang Hu, Zhiliang Jin
• 收稿日期:2020-08-13 录用日期:2020-09-07 发布日期:2020-09-11
• 通讯作者: 郝旭强,靳治良 E-mail:haoxuqiang@126.com;zl-jin@nun.edu.cn
• 基金资助:
This work was financially supported by the Natural Science Foundation of the Ningxia Hui Autonomous Region, China (2020AAC02026, 2020AAC03204), the Open Project of State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering, Ningxia University, China (2019-KF-36), the Ningxia Low-Grade Resource High Value Utilization and Environmental Chemical Integration Technology Innovation Team Project, North Minzu University, China

### High Efficiency Electron Transfer Realized over NiS2/MoSe2 S-Scheme Heterojunction in Photocatalytic Hydrogen Evolution

Yang Liu1, Xuqiang Hao1,*(), Haiqiang Hu2, Zhiliang Jin1,*()

1. 1 School of Chemistry and Chemical Engineering, Ningxia Key Laboratory of Solar Chemical Conversion Technology, Key Laboratory for Chemical Engineering and Technology, State Ethnic Affairs Commission, North Minzu University, Yinchuan 750021, China
2 College of Mechanical and Automotive Engineering, Yinchuan University of Energy, Yinchuan 750100, China
• Received:2020-08-13 Accepted:2020-09-07 Published:2020-09-11
• Contact: Xuqiang Hao,Zhiliang Jin E-mail:haoxuqiang@126.com;zl-jin@nun.edu.cn
• About author:Zhiliang Jin, Email: zl-jin@nun.edu.cn; Tel.: +86-13893316102 (Z.J.)
Xuqiang Hao, Email: haoxuqiang@126.com. +86-18095117159 (X.H.)
• Supported by:
This work was financially supported by the Natural Science Foundation of the Ningxia Hui Autonomous Region, China (2020AAC02026, 2020AAC03204), the Open Project of State Key Laboratory of High-Efficiency Utilization of Coal and Green Chemical Engineering, Ningxia University, China (2019-KF-36), the Ningxia Low-Grade Resource High Value Utilization and Environmental Chemical Integration Technology Innovation Team Project, North Minzu University, China

S型异质结的提出是光催化领域发展的一个重要新理论。本研究通过典型的溶剂热法制备了NiS2和MoSe2，并通过原位生长的方法将二者复合，构建了S型异质结。所得的复合材料在光催化析氢中显示了优异的性能，产氢速率达7 mmol·h1·g-1，是纯NiS2和MoSe2的2.05倍和2.44倍。进一步研究证实，NiS2和MoSe2耦合可以增强对光吸收强度。与纯NiS2和MoSe2相比，NiS2/MoSe2更高的光电流密度和更低的阴极电流及更低的电化学阻抗均证明了NiS2/MoSe2复合物可以有效促进光生电子的转移。同时，更低的荧光强度表明了NiS2/MoSe2复合物对电子-空穴再次复合的有效抑制，这为光催化析氢反应提供了有利的条件。另一方面，通过扫描电子显微镜和透射电子显微镜发现，MoSe2作为一种无定型样品包围NiS2纳米微球，这大大增加了两者之间的接触面积, 从而增加了反应的活性位点。其次，在该光反应体系中，曙红(EY)作为一种光敏剂，有效地增强了催化剂对光的吸收。同时，在敏化过程中，曙红提供了电子给催化剂，这有效提高了光催化反应效率。S型异质结的建立有助于提高反应体系的氧化还原能力，是光催化还原水产氢反应析氢效果提高的主要原因。通过模特肖特基和光子能量曲线确定NiS2和MoSe2的导带、价带位置，进一步证明了S型异质结的建立。这项工作为研究S型异质结有效提高光催化制氢效率提供了新的参考。

Abstract:

S-scheme heterojunction is a major breakthrough in the field of photocatalysis. In this study, NiS2 and MoSe2 were prepared by a typical solvothermal method, and compounded by an in situ growth method to construct an S-scheme heterojunction. The obtained composite showed excellent performance in photocatalytic hydrogen evolution; the hydrogen production rate was approximately 7 mmol·h-1·g-1, which was 2.05 times and 2.44 times those of pure NiS2 and MoSe2, respectively. Through a series of characterizations, it was found that NiS2 and MoSe2 coupling can enhance the light absorption intensity, which is vital for the light reaction system. The efficiency of electron-hole pair separation is also among the important factors restricting photocatalytic reactions. Compared with pure NiS2 and MoSe2, NiS2/MoSe2 exhibited a higher photocurrent density, lower cathode current, and lower electrochemical impedance, which proves that the NiS2/MoSe2 complex can effectively promote photogenerated electron transfer. Simultaneously, the lower emission intensity of fluorescence indicated effective inhibition of electron-hole recombination in the NiS2/MoSe2 complex, which is favorable for the photocatalytic hydrogen evolution reaction. Further, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that MoSe2 is an amorphous sample surrounded by the NiS2 nanomicrosphere, which greatly increased the contact area between the two, thus increasing the active site of the reaction. Secondly, as a photosensitizer, Eosin Y (EY) effectively enhanced the absorption of light by the catalyst in the photoreaction system. Meanwhile, during sensitization, electrons were provided to the catalyst, which effectively improved the photocatalytic reaction efficiency. The establishment of S-scheme heterojunctions contributed to improving the redox capacity of the reaction system and was the most important link in the photocatalytic hydrogen reduction of aquatic products. It was also the main reason for the improvement of the hydrogen evolution effect in this study. The locations of the conduction band and valence band of NiS2 and MoSe2 were determined by Mott-Schottky plots and photon energy curves, and further proved the establishment of the S-scheme heterojunction. This work provides a new reference for studying the S-scheme heterojunction to effectively improve the photocatalytic hydrogen production efficiency.

MSC2000:

• O644