Chahkandi Mohammad, Zargazi Mahboobeh, Ahmadi Afsaneh, Koushki Ehsan, Ghasedi Arman
Department of Chemistry, Hakim Sabzevari University Sabzevar 96179-76487 Iran
Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad Mashhad 91775 Iran.
RSC Adv. 2021 Sep 22;11(50):31174-31188. doi: 10.1039/d1ra05259d. eCollection 2021 Sep 21.
The interesting g-CN nanosheet morphology has drawn huge attention in photocatalytic applications because of its special features. Nonetheless, the relative activity of these nanosheets is still controversial due to the low available active sites and the high recombination probability of photo-induced charge carriers. In this work, sol-gel approach was applied to synthesize holey g-CN nanosheets/hydroxyapatite (HAp) nanospheres with plentiful in-plane holes. Herein, the presence of Ca plays a key role in the formation of holey defects on 2D g-CN. In-plane holes provide nanosheets with more active edges and diffusion channelsv, resulting in a tremendous enhanced mass and photo-induced charge transfer speed. Moreover, the holes make highly numbered boundaries, which lead to the prevention of aggregation. On the other hand, distributed nano-HAp spheres on these nanosheets can form effective heterojunctions having high photo-degradation ability of pollutants. Intrinsic O-vacancies inside HAp unit cells mainly affect the capture of photogenerated electrons, pollutant molecules, and O gas. The synergistic presence of O-vacancies and holey defects (C-vacancies) on 2D g-CN plays a key role in raising the photocatalytic performance of holey g-CN/HAp. It can be concluded that the proposed preparation method is a promising approach for simultaneous synthesis of holey g-CN and surface heterojunctions of Ca-based materials. This new structure has shown significant degradation ability of bisphenol A, a prominent pollutant, with a low amount (0.01 g) and short time.
有趣的石墨相氮化碳（g-CN）纳米片形态因其特殊特性在光催化应用中引起了极大关注。尽管如此，由于可用活性位点较少以及光生载流子的高复合概率，这些纳米片的相对活性仍存在争议。在这项工作中，采用溶胶-凝胶法合成了具有大量面内孔洞的多孔g-CN纳米片/羟基磷灰石（HAp）纳米球。在此，Ca的存在在二维g-CN上形成多孔缺陷方面起着关键作用。面内孔洞为纳米片提供了更多的活性边缘和扩散通道，从而极大地提高了质量和光生电荷转移速度。此外，这些孔洞形成了大量的边界，从而防止了聚集。另一方面，分布在这些纳米片上的纳米级HAp球体能形成具有高污染物光降解能力的有效异质结。HAp晶胞内部的固有氧空位主要影响光生电子、污染物分子和氧气的捕获。二维g-CN上氧空位和多孔缺陷（碳空位）的协同存在在提高多孔g-CN/HAp的光催化性能方面起着关键作用。可以得出结论，所提出的制备方法是同时合成多孔g-CN和钙基材料表面异质结的一种有前景的方法。这种新结构在低用量（0.01 g）和短时间内对双酚A（一种突出的污染物）显示出显著的降解能力。
