摘要
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NiS_(2)和MoSe_(2),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7mmol·h^(-1)·g^(-1),是纯NiS_(2)和MoSe_(2)的2.05倍和2.44倍。进一步研究证实,NiS_(2)和MoSe_(2)耦合可以增强对光吸收强度。与纯NiS_(2)和MoSe_(2)相比,NiS_(2)/MoSe_(2)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NiS_(2)/MoSe_(2)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NiS_(2)/MoSe_(2)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,MoSe_(2)作为一种无定型样品包围NiS_(2)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NiS_(2)和MoSe_(2)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。
S-scheme heterojunction is a major breakthrough in the field of photocatalysis.In this study,NiS_(2) and MoSe_(2) 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 NiS_(2) and MoSe_(2),respectively.Through a series of characterizations,it was found that NiS_(2) and MoSe_(2) 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 NiS_(2) and MoSe_(2),NiS_(2)/MoSe_(2) exhibited a higher photocurrent density,lower cathode current,and lower electrochemical impedance,which proves that the NiS_(2)/MoSe_(2) complex can effectively promote photogenerated electron transfer.Simultaneously,the lower emission intensity of fluorescence indicated effective inhibition of electron-hole recombination in the NiS_(2)/MoSe_(2) complex,which is favorable for the photocatalytic hydrogen evolution reaction.Further,scanning electron microscopy(SEM)and transmission electron microscopy(TEM)showed that MoSe_(2) is an amorphous sample surrounded by the NiS_(2) 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 imp
作者
刘阳
郝旭强
胡海强
靳治良
Yang Liu;Xuqiang Hao;Haiqiang Hu;Zhiliang Jin(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;College of Mechanical and Automotive Engineering,Yinchuan University of Energy,Yinchuan 750100,China)
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2021年第6期107-118,共12页
Acta Physico-Chimica Sinica
基金
宁夏自然科学基金重点项目(2020AAC02026)
宁夏自然科学基金一般项目(2020AAC03204)
省部共建煤炭高效利用与绿色化工国家重点实验室开放课题重点项目(2019-KF-36)
宁夏低品位资源高值化利用及环境化工一体化技术创新团队资助。
