Oxygen-doped (O-doped) graphitic carbon nitride (g-C₃N₄) usually presents excellent photocatalytic activity compared to pristine g-C₃N₄ with the common O_N2-doping. However, there are very few research studies concerned with the O_N1-doped g-C₃N₄. Herein, g-C₃N₄ nanosheet samples with two different O-doping positions (O_N1 and O_N2) were prepared and characterized. Different O_N1-doping contents were achieved via the polycondensation of g-C₃N₄ under different calcination temperatures for the precursor urea. Results showed that the as-prepared O_N1-doped g-C₃N₄ nanosheets with an oxygen content of 2.16% demonstrated the highest photocatalytic activity in degrading rhodamine B (RhB, 10 mg L⁻¹) with a degradation rate as high as 99% in 3 min under visible light irradiation, which is the best g-C₃N₄ photocatalyst compared to the literature reports for RhB degradation. The improved degradation was related to the decreased oxygen content of O_N1-doped g-C₃N₄ nanosheets instead of normal O_N2-doping, which was also confirmed by DFT computation.

中文翻译：

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低ON1掺杂含量的石墨状氮化碳纳米片可作为有效的光催化剂降解有机污染物

与普通的O _N2掺杂的原始gC ₃ N ₄相比，氧掺杂（O掺杂）的石墨氮化碳（gC ₃ N ₄）通常具有出色的光催化活性。但是，很少有研究涉及掺杂有O _N1的gC ₃ N ₄。在此，制备并表征了具有两个不同的O掺杂位置（O _N1和O _N2）的gC ₃ N ₄纳米片样品。通过gC ₃ N ₄的缩聚反应获得不同的O _N1掺杂含量在不同的煅烧温度下，前体尿素。结果表明，氧含量为2.16％的制备的O _N1掺杂的gC ₃ N ₄纳米片表现出最高的光催化降解罗丹明B的活性（RhB，10 mg L ^-1），降解率高达99％。在可见光照射下3分钟内，与文献报道的RhB降解相比，这是最好的gC ₃ N ₄光催化剂。降解的改善与掺O _N1的gC ₃ N ₄纳米片而不是正常的O _N2的氧含量降低有关-掺杂，这也通过DFT计算得到了证实。