Carbon dots (CDs), as a unique zero-dimensional member of carbon materials, have attracted numerous attentions for their potential applications in optoelectronic, biological, and energy related fields. Recently, CDs as catalysts for energy conversion reactions under multi-physical conditions such as light and/or electricity have grown into a research frontier due to their advantages of high visible light utilization, fast migration of charge carriers, efficient surface redox reactions and good electrical conductivity. In this review, we summarize the fabrication methods of CDs and corresponding CD nanocomposites, including the strategies of surface modification and heteroatom doping. The properties of CDs that concerned to the photo- and electro-catalysis are highlighted and detailed corresponding applications are listed. More importantly, as new non-contact detection technologies, transient photo-induced voltage/current have been developed to detect and study the charge transfer kinetics, which can sensitively reflect the complex electron separation and transfer behavior in photo-/electro-catalysts. The development and application of the techniques are reviewed. Finally, we discuss and outline the major challenges and opportunities for future CD-based catalysts, and the needs and expectations for the development of novel characterization technologies.

利用湿化学法在FTO玻璃基底上制备了高度规整的ZnO纳米棒阵列(ZnO NRAs), 以此为衬底, 采用磁控溅射法在ZnO NRAs表面沉积Cu2O薄膜。分别用X射线衍射仪、X射线光电子能谱、扫描电镜、光致光谱、紫外可见分光光度计和电化学工作站对样品的物相、形貌、吸收光谱、光电性能进行了表征, 用甲基橙(MO)模拟有机物废水研究复合材料的光催化性能。结果表明: ZnO纳米棒为六方纤锌矿结构, 其直径约为80～100 nm, 长约2～3 μm, 棒间距约100～120 nm。立方晶系的Cu2O颗粒直径约为100～300 nm, 形成致密膜层并紧密覆盖在ZnO NRAs表面上, 构成ZnO/Cu2O异质结纳米阵列(ZnO/Cu2O HNRAs)结构。与纯ZnO NRAs和Cu2O相比, ZnO/Cu2O HNRAs在可见光范围内的吸收显著增强, 吸收波长向可见光方向偏移。ZnO/Cu2O HNRAs的载流子传递界面的电荷转移速度快, 有效促进了光生电子和空穴的分离。在紫外-可见光照射65 min后, ZnO/Cu2O HNRAs的降解效率为94%, 分别是纯ZnO NRAs和Cu2O的18倍和1.7倍。