The rapid recombination of photogenerated charges is the primary bottleneck hindering photocatalytic hydrogen generation with graphitic carbon nitride (g-C₃N₄). Herein, by introducing methyl viologen (MV) into the carbon nitride framework, CN-MV-x with enhanced photoinduced charge carrier separation is fabricated. The surface chemistry and photoelectrochemical properties of CN-MV-x samples are greatly enhanced. Owing to the increased charge separation with electron extraction by doped MV, the highest hydrogen evolution rate of 1.65 mmol g⁻¹ h⁻¹ is achieved by the CN-MV-x photocatalyst doped with 10 mmol MV (CN-MV-10). More impressively, CN-MV-10 also shows an extraordinary electron storage ability, which powers time-delayed hydrogen production in the dark after light illumination. Further analysis indicates that this time-delayed hydrogen evolution ability is ascribed to electron accumulation in the conduction band of carbon nitride. This study provides a new route to improve photoinduced charge separation by introducing redox species.

中文翻译：

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紫精掺杂诱导氮化碳中的电荷存储以增强光催化制氢


光生电荷的快速复合是阻碍石墨氮化碳 （g-C₃， N₄） 光催化制氢的主要瓶颈。在此，通过将甲基紫精 （MV） 引入氮化碳框架中，制备了具有增强光诱导载流子分离的 CN-MV-x。CN-MV-x 样品的表面化学和光电化学性能大大增强。由于掺杂 MV 的电子萃取增加了电荷分离，因此掺杂 10 mmol MV （CN-MV-10） 的 CN-MV-x 光催化剂实现了 1.65 mmol ^{g-1 h-1} 的最高析氢速率。更令人印象深刻的是，CN-MV-10 还显示出非凡的电子存储能力，可在光线照射后的黑暗中为延时制氢提供动力。进一步的分析表明，这种时间延迟析氢能力归因于氮化碳导带中的电子积累。本研究提供了一种通过引入氧化还原物质来改善光诱导电荷分离的新途径。