The pursuit of photodegrading environmental pollutants while efficiently utilizing solar energy remains a pivotal endeavor. Herein, Ag₂S quantum dots (QDs)/reduced graphene oxide (rGO) composites with Ag₂S QDs dispersed on porous stereoscopic rGO-based network were synthesized through a facile hydrothermal process without the addition of any other reducing agent or cross-linker. The as-obtained composites exhibited enhanced adsorption and photocatalysis performance under visible light because of the individual and synergistic effects. The hierarchically stereoscopic structure led to outstanding adsorption ability due to large specific surface area and spongy nature, which facilitated connection between the contaminants and the photocatalytic sites. The incorporation of rGO also suppressed the recombination of electron–hole pairs in the semiconductor and favored the separation from wastewater. Ag₂S QDs, whose properties were influenced by quantum size effect, displayed a widened bandgap of 1.82 eV rather than initial 0.92 eV, attributing to stronger redox potential to degrade organic pollutants while efficiently absorbing the visible portion of solar light. With methyl orange as the model pollutant, the comprehensively optimized sample obtained at 150 °C exhibited adsorption capacity of 260 mg g⁻¹ at 25 °C and photodegradation rate 7.8 times that of commercial TiO₂ nanoparticles under visible light. Phenol was also analyzed to remove the influence of photosensitization of dyes. Our investigation gives a new insight into the design and fabrication of narrow band semiconductor/rGO composites with enhanced adsorption and photocatalysis.

中文翻译：

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三维带隙调谐的Ag ₂ S量子点/还原的氧化石墨烯复合材料，在可见光下具有增强的吸附和光催化作用†

在有效利用太阳能的同时追求光降解环境污染物仍然是一项关键性的工作。本文中，Ag ₂ S量子点（QDs）/还原氧化石墨烯（rGO）与Ag _2的复合材料通过简便的水热过程合成了分散在基于多孔立体rGO的多孔网络上的S QD，而无需添加任何其他还原剂或交联剂。所获得的复合物由于单独和协同作用而在可见光下表现出增强的吸附和光催化性能。由于大的比表面积和海绵状性质，分级的立体结构导致了出色的吸附能力，这促进了污染物与光催化位点之间的连接。rGO的加入还抑制了半导体中电子-空穴对的重组，有利于从废水中分离。银₂S QD的性能受量子尺寸效应的影响，其带隙增宽为1.82 eV，而不是初始的0.92 eV，这归因于较强的氧化还原电势，可降解有机污染物，同时有效吸收太阳光的可见部分。以甲基橙为模型污染物，在150°C下获得的经过全面优化的样品在25°C下的吸附容量为260 mg g ^-1，在可见光下的光降解速率为市售TiO ₂纳米颗粒的7.8倍。还对苯酚进行了分析，以消除染料光敏性的影响。我们的研究为具有增强的吸附和光催化作用的窄带半导体/ rGO复合材料的设计和制造提供了新的见识。