NiMoO_(4)/ZnIn_(2)S_(4)S-scheme异质结的制备及光催化产氢性能增强机制

Preparation of NiMoO_(4)/ZnIn_(2)S_(4)S-Scheme Heterojunctions and Enhancement Mechanism of Photocatalytic Hydrogen Production

首先通过水热法制备得到NiMoO_(4)·x H_(2)O前驱体,再经高温煅烧得到NiMoO_(4)纳米棒,最后通过超声混合及溶剂蒸干处理将NiMoO_(4)与ZnIn_(2)S_(4)复合构建了NiMoO_(4)/ZnIn_(2)S_(4)S-scheme异质结光催化剂。研究结果表明,NiMoO_(4)质量分数为10.7%时,复合材料(10.7-NiMoO_(4)/ZnIn_(2)S_(4))具有较好的载流子分离效率,较低的界面电荷转移阻力和较大的电化学活性面积。在300 W氙灯照射下,其产氢速率可达29.04 mmol·g^(-1)·h^(-1),约为单体ZnIn_(2)S_(4)(5.58 mmol·g^(-1)·h^(-1))的5.20倍。自由基捕获实验及能带结构分析表明,NiMoO_(4)和ZnIn_(2)S_(4)之间形成了S-scheme电荷转移机制,不仅促进了载流子的分离与迁移,而且保留了较强的氧化还原能力。此外,NiMoO_(4)的引入提高了异质结的电化学活性面积,以上因素协同提高了体系的光催化析氢性能。

In this work,NiMoO_(4)·x H_(2)O precursor was prepared by a hydrothermal method,and then NiMoO_(4)nanorod was obtained after calcination of NiMoO_(4)·x H_(2)O precursor.Finally,the NiMoO_(4)/ZnIn_(2)S_(4)S-scheme heterojunction was constructed by combining ZnIn_(2)S_(4)with NiMoO_(4)using a solvent evaporation process.The results show that 10.7%-NiMoO_(4)/ZnIn_(2)S_(4)with a NiMoO_(4)mass ratio of 10.7%has better carrier separation efficiency,lower interface charge transfer resistance,and larger electrochemical active area.The highest hydrogen production rate can reach 29.04 mmol·g^(-1)·h^(-1)under 300 W Xe lamp irradiation,which is about 5.20 times of the ZnIn_(2)S_(4)(5.58 mmol·g^(-1)·h^(-1)).The experimental results of radical trapping and band structure analysis suggest that S-scheme charge transfer route was formed between NiMoO_(4)and ZnIn_(2)S_(4),which not only promotes the separation and migration of charge carriers,but also retains strong capacity of charge carriers.In addition,the introduction of NiMoO_(4)improved the electrochemical active area of the heterojunction,and the above factors jointly improved the photocatalytic hydrogen evolution rate of the system.