Graphene quantum dots (GQD) are promising visible‐light photocatalysts for organic dye degradation. Besides having improved visible‐light activity compared with commercial TiO₂, GQD are versatile photocatalysts as their chemical composition and, consequently, optical properties can be tuned synthetically, with a direct impact on photoactivity. However, there is a lack of systematic comparative studies to benchmark GQD photocatalytic performance and relate it to their intrinsic properties. This is undertaken in this work for three types of GQD, which are prepared using well‐established synthetic methods representative of top‐down and bottom‐up approaches using different precursors. Resulting GQD are similar in size but differ in chemical composition, crystallinity, bandgap (ranging from 2.63 to 3.63 eV) and visible‐light absorptivity. Photoactivity measurements under comparable experimental conditions (visible‐light illumination) reveal enormous activity differences for rhodamine B (RhB) degradation, with up to tenfold higher degradation yields at the same time for certain GQD types. The enormous influence of intrinsic and tunable GQD factors, like visible‐light absorptivity and surface charge, on their photoactivity for the degradation of organic dyes is demonstrated, highlighting the importance of tailoring such parameters for enhanced photocatalytic performance. A plausible mechanism for GQD‐catalyzed photodegradation of RhB is also proposed.

中文翻译：

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石墨烯量子点对有机染料降解的光催化活性的影响因素

石墨烯量子点（GQD）是用于有机染料降解的有前途的可见光光催化剂。与商用TiO ₂相比，除了具有改善的可见光活性外GQD是一种多功能的光催化剂，因为它们的化学组成，因此可以合成光学性质的变化，直接影响光活性。但是，缺乏系统的比较研究来基准化GQD光催化性能并将其与它们的内在特性联系起来。这是针对三种类型的GQD进行的，这三种类型的GQD是使用成熟的合成方法制备的，这些方法代表使用不同前体的自上而下和自下而上的方法。产生的GQD大小相似，但化学成分，结晶度，带隙（范围为2.63至3.63 eV）和可见光吸收率不同。在相当的实验条件下（可见光照明）进行的光活性测量表明，若丹明B（RhB）的降解存在巨大的活性差异，对于某些GQD类型，同时具有高达十倍的较高降解率。事实证明，内在和可调的GQD因子（如可见光吸收率和表面电荷）对其光活性对有机染料降解的巨大影响，凸显了调整此类参数以增强光催化性能的重要性。还提出了GQD催化RhB光降解的合理机制。