Huang Xiaoyan, Huang Yu, Yan Fengpo, Xue Xiaogang, Zhang Kexiang, Cai Ping, Zhang Xiaowen, Zhang Xiuyun
School of Materials Science and Engineering, Guangxi Key Laboratory of Information Materials, Guilin University of Electronic Technology, Guilin 541004, People's Republic of China.
Key Laboratory of Green Perovskites Application of Fujian Province Universities, Fujian Jiangxia University, Fuzhou 350108, People's Republic of China.
J Colloid Interface Sci. 2021 Jul;593:222-230. doi: 10.1016/j.jcis.2021.02.091. Epub 2021 Mar 9.
Surface engineering of quantum dots (QDs) plays critical roles in tailoring carriers' dynamics of I-III-VI QDs via the interplay of QDs in aggregates or assembly, thus influencing their photocatalytic activities. In this work, an aqueous synthesis and the followed pH tuned oriented assembly method are developed to prepare network-like aggregates, dispersion, or sheet-like assembly of GSH-capped Silver Indium Sulfide (AIS). FTIR, DLS, and HRTEM investigation revealed that surface protonation or deprotonation of QDs occurred at pH < 6 or pH > 12 favors the formation of network-like aggregates with various defects or sheet-like assembly with perfect crystal lattice, respectively, via the surface charge induced interaction among AIS QDs. Further UV-vis, steady and transient PL investigation confirm the narrowed band gaps and the prolonged PL lifetime of the acidic network-like aggregates. As a result, the optimized network-like aggregates (3.0-AIS) exhibits superior photocatalytic H evolution (PHE) rates (5.2 mmol·g·h), about 113 times that of alkaline sheet-like assembly (13.0-AIS) or 2.7 times higher than that of dispersed AIS QDs (AIS-8.0). The formation of defects and their roles in PHE mechanisms are discussed. This work is expected to give some new insight for designing efficient non-cadmium/non-novel metal I-III-VI photocatalysts for boosting PHE.
量子点（QDs）的表面工程通过聚集体或组装体中量子点的相互作用，在调控I-III-VI族量子点载流子动力学方面起着关键作用，从而影响其光催化活性。在这项工作中，开发了一种水相合成及随后的pH调节取向组装方法，以制备谷胱甘肽包覆的硫化银铟（AIS）的网络状聚集体、分散体或片状组装体。傅里叶变换红外光谱（FTIR）、动态光散射（DLS）和高分辨透射电子显微镜（HRTEM）研究表明，在pH < 6或pH > 12时，量子点的表面质子化或去质子化分别有利于通过AIS量子点之间的表面电荷诱导相互作用形成具有各种缺陷的网络状聚集体或具有完美晶格的片状组装体。进一步的紫外可见光谱、稳态和瞬态光致发光（PL）研究证实了酸性网络状聚集体的带隙变窄和PL寿命延长。结果，优化后的网络状聚集体（3.0-AIS）表现出优异的光催化析氢（PHE）速率（5.2 mmol·g·h），约为碱性片状组装体（13.0-AIS）的113倍，或比分散的AIS量子点（AIS-8.0）高2.7倍。讨论了缺陷的形成及其在PHE机制中的作用。这项工作有望为设计高效的非镉/非新型金属I-III-VI光催化剂以促进PHE提供一些新的见解。
