The adsorption of the Fe²⁺ and Fe³⁺ cations on four surface models of graphitic carbon nitride quantum dots, including planar and corrugated nanosheets of triazine and heptazine structures has been explored using density functional theory. The adsorption was most favorable on hollow sites but with different coordination numbers and geometrical configurations. A remarkable decrease in the energy gap of the semiconductor (e.g., from 4.10 to 0.01 eV with the buckled triazine-type sensor) delineated the high capability of the 2D material toward the detection of iron cations, particularly the Fe³⁺ analyte. Remarkable charge transfers (in the range of 0.688–0.908 e and 1.692–1.794 e for Fe²⁺ and Fe³⁺, respectively) from the surface to the analyte were identified from the QTAIM charge analysis. Ignoring the surface curvature could overestimate the adsorption energy while underestimating the energy gap and charge transfer of both types of graphitic carbon nitride. The LOL profiles and density of electronic states revealed the mechanism and nature of the interactions.

中文翻译：

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原始的庚烷和三嗪聚合的氮化碳量子点和平面结构上的铁（II，III）阳离子吸附：理论见解

利用密度泛函理论研究了Fe ²⁺和Fe ³⁺阳离子在石墨化碳氮化物量子点的四个表面模型上的吸附，包括三嗪和庚嗪结构的平面和波纹状纳米片。吸附在中空部位最有利，但配位数和几何构型不同。半导体的能隙显着降低（例如，使用弯曲的三嗪型传感器从4.10降低至0.01 eV）表明2D材料对铁阳离子（特别是Fe ³⁺分析物）的检测能力强。显着的电荷转移（Fe ²⁺和Fe ³⁺在0.688–0.908 e和1.692–1.794 e范围内分别从表面到分析物进行QTAIM电荷分析。忽略表面曲率可能会高估吸附能，同时会低估两种石墨氮化碳的能隙和电荷转移。LOL分布和电子态密度揭示了相互作用的机理和性质。