Abstract The photocatalytic production of syngas using a noble-metal-free catalytic system is a promising approach for renewable energy and environmental sustainability. In this study, we demonstrate an efficient catalytic system formed by integrating Co single sites, which act as the active sites, in covalent triazine frameworks (CTFs), which act as the photoabsorber, for the photocatalytic production of syngas from CO2 in aqueous solution. The enhanced light absorption of the CTFs, which contain intramolecular heterojunctions, in conjunction with 0.8 mmol L−1 of the Co complex enables excellent syngas production with a yield of 3303 μmol g−1 (CO:H2 = 1.4:1) in 10 h, which is about three times greater than that achieved using CTF without a heterojunction. In the photocatalytic reaction, the coordinated single Co centers accept the photogenerated electrons from the CTF, and serve as active sites for CO2 conversion through an adsorption-activation-reaction mechanism. Theoretical calculations further reveal that the intramolecular heterojunctions highly promote photogenerated charge separation, thus boosting photocatalytic syngas production. This work reveals the promising potential of CTFs for single-metal-site-based photocatalysis.

中文翻译：

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共价三嗪骨架中 Co 单位点的封装用于光催化生产合成气

摘要 使用无贵金属催化体系光催化生产合成气是可再生能源和环境可持续性的一种有前途的方法。在这项研究中，我们展示了一种有效的催化系统，该系统通过将作为活性位点的 Co 单点整合到作为光吸收剂的共价三嗪骨架 (CTF) 中，用于从水溶液中的 CO2 光催化生产合成气。包含分子内异质结的 CTF 的光吸收增强，再加上 0.8 mmol L-1 的 Co 配合物，可在 10 小时内以 3303 μmol g-1（CO:H2 = 1.4:1）的产率生产出色的合成气，这大约是使用没有异质结的 CTF 实现的结果的三倍。在光催化反应中，协调的单个 Co 中心接受来自 CTF 的光生电子，并通过吸附-活化-反应机制作为 CO2 转化的活性位点。理论计算进一步表明，分子内异质结高度促进光生电荷分离，从而促进光催化合成气的产生。这项工作揭示了 CTF 在基于单金属位点的光催化方面的潜力。