Visible-light-responsive nanocarbon was systematically synthesized via a one-step hydrothermal method, using citric acid and Congo Red; this nanocarbon exhibited visible-light absorption at 516 nm and photocatalytic activity for the carbon–carbon bond-forming reaction between benzylamine and ethyl cyanoacetate. Mechanistic investigations proved that this system generates radicals and the reactions proceed via radical pathways, which are confirmed by electron spin resonance. A metal-free, mildly conditioned, and recyclable photocatalytic reaction was achieved by the visible-light-responsive nanocarbon system.

中文翻译：

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可见光响应纳米碳的合成及其在光催化碳-碳键形成中的应用

使用柠檬酸和刚果红，通过一步水热法系统合成可见光响应纳米碳；这种纳米碳在 516 nm 处表现出可见光吸收，并对苄胺和氰基乙酸乙酯之间的碳-碳键形成反应具有光催化活性。机理研究证明该系统会产生自由基，并且反应通过自由基途径进行，这一点得到了电子自旋共振的证实。通过可见光响应纳米碳系统实现了无金属、温和调节且可回收的光催化反应。