Decoupling hydrogen production from diurnal cycles is challenging in solar energy conversion. Recently, defect-modified K-doped carbon nitride has demonstrated the potential to realize this unique property. However, the concomitant undesirable defects during eutectic treatment, such as triazine ring insertion, impose substantial limitations on the decoupling performance. In this study, a one-step eutectic method assisted by CCl4 was developed, which removed the detrimental triazine-based defects while introducing beneficial nitrogen vacancies. The engineered structure efficiently enhances visible light absorption, and spatially separates the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO). The localized LUMO on N-K sites serves as an electron reservoir, facilitating carrier separation and inhibiting the recombination. Consequently, one of the highest timely light-driven activities among polymeric photocatalysts was achieved, reaching 2557 times the H2 production rate compared to the un-engineered counterpart. More significantly, the electron reservoir could store active electrons for several weeks, successfully enabling delayed on-demand solar H2 production and decoupling H2 evolution from diurnal cycles. This study effectively achieves both spatial and temporal separation of light absorption, solar storage, and release through defect tailoring, which is expected to advance the development of decoupled catalytic studies.

中文翻译：

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掺钾碳氮化物的缺陷定制：实现光反应和暗反应的有效解耦，以实现及时和延迟的按需太阳能制氢


在太阳能转换中，将氢气生产与昼夜循环脱钩是一项挑战。最近，缺陷改性的钾掺杂碳氮化物已经证明了实现这种独特性能的潜力。然而，共晶处理过程中伴随的不良缺陷，例如三嗪环插入，对去耦性能造成了很大的限制。在本研究中，开发了一种由 CCl4 辅助的一步共晶方法，该方法消除了有害的三嗪基缺陷，同时引入了有益的氮空位。该工程结构有效增强可见光吸收，并在空间上分离最高占据分子轨道（HOMO）和最低未占据分子轨道（LUMO）。 NK 位点上的局域 LUMO 作为电子库，促进载流子分离并抑制复合。因此，实现了聚合物光催化剂中最高的及时光驱动活性之一，与未经工程设计的对应物相比，氢气生产率达到了 2557 倍。更重要的是，电子库可以存储活性电子数周，成功地实现了延迟按需太阳能氢气生产，并使氢气的演化与昼夜循环脱钩。该研究通过缺陷定制有效实现了光吸收、太阳能存储和释放的空间和时间分离，有望推动解耦催化研究的发展。