H₂O₂ has a wide range of uses as an oxidant and is also utilized as a high density and environmentally friendly fuel. In this study, crystalline g-C₃N₄ was modified with K⁺, Ni and N-doped carbon by thermal-polymerization of Ni²⁺-anchored and polyvinyl pyrrolidone-encapsulated melamine-cyanuric acid supramolecules, followed by re-calcination in a KCl–LiCl mixture. The obtained strip-like g-C₃N₄ nanocrystals exhibited high charge separation efficiency and good light absorption capability. Density-functional theory calculations confirmed that the orbital hybridization of Ni–N atoms enabled the formation of charge-transfer channels, which can capture electrons, achieve enhanced oxygen adsorption and reduction via a two-electron pathway. Under the synergistic effects of K⁺, Ni and N-doped carbon dopants and crystallinity, the obtained sample exhibited high photocatalytic H₂O₂ yields of 79.6 μM in O₂-saturated pure water, which was 10-fold higher than the yield using pristine g-C₃N₄. This work provides a novel design for production of highly efficient photocatalysts for H₂O₂ production.

中文翻译：

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K+、Ni 和碳共改性促进双电子 O2 还原，用于结晶氮化碳光催化生产 H2O2

H ₂ O ₂作为氧化剂具有广泛的用途，并且还被用作高密度和环境友好的燃料。在这项研究中，通过 Ni ²⁺锚定和聚乙烯吡咯烷酮包封的三聚氰胺-氰尿酸超分子的热聚合，用 K ⁺、Ni 和 N 掺杂的碳对结晶 gC ₃ N ₄进行改性，然后在 KCl 中重新煅烧-氯化锂混合物。所得条状gC ₃ N ₄纳米晶体表现出高的电荷分离效率和良好的光吸收能力。密度泛函理论计算证实，Ni-N 原子的轨道杂化能够形成电荷转移通道，该通道可以捕获电子，通过双电子途径实现增强的氧吸附和还原。在 K ⁺、Ni 和 N 掺杂的碳掺杂剂和结晶度的协同作用下，所得样品在 O ₂饱和纯水中表现出79.6 μM 的高光催化 H ₂ O ₂产率，比使用原始 gC ₃ N ₄. 这项工作为生产用于生产 H ₂ O _{2 的}高效光催化剂提供了一种新颖的设计。