ABSTRACT The applicability of four surface models of graphitic carbon nitride (planar and corrugated nanosheets of triazine and heptazine structures) to detect hexavalent chromium from contaminated environments was investigated theoretically. The sensing was most favourable on hollow sites but with different coordination numbers and geometrical configurations. A substantial variation in the gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of the 2D material (e.g. from 4.12 to 0.36 eV in the case of buckled heptazine structure) delineated the high capability of the sensor toward the detection of the chromium ion. Remarkable charge transfers (4.466–4.558 e) from the sensor to the analyte were evident from the topological analysis. Neglecting the surface corrugation could overestimate the adsorption energy while underestimating the HOMO–LUMO gap of both types of graphitic carbon nitride. The localised orbital locator (LOL) profiles revealed the ionic nature of the interactions.

中文翻译：

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在七嗪和三嗪结构的屈曲和平面聚合氮化碳纳米片上感测六价铬的理论见解

摘要 从理论上研究了石墨氮化碳的四种表面模型（三嗪和七嗪结构的平面和波纹纳米片）在检测污染环境中的六价铬方面的适用性。传感在空心位置最有利，但具有不同的配位数和几何配置。二维材料的最高占据分子轨道 (HOMO) 和最低未占据分子轨道 (LUMO) 之间的差距的显着变化（例如，在弯曲的七嗪结构的情况下，从 4.12 到 0.36 eV）描绘了传感器的高性能用于检测铬离子。从拓扑分析可以明显看出从传感器到分析物的显着电荷转移 (4.466–4.558 e)。忽略表面波纹会高估吸附能，而低估两种石墨氮化碳的 HOMO-LUMO 间隙。局部轨道定位器 (LOL) 剖面揭示了相互作用的离子性质。