Hydrogen production from overall water splitting by photocatalyst is an ultimate clean and renewable energy strategy. Recent developments show that carbon based materials are considerable photocatalysts for overall water splitting under visible light because of their high activity, high stability, low-cost, easy fabrication and structural diversity. However, it still lacks a systematic study and deep understanding on the working mechanism of the carbon based photocatalysts. Herein, we show the fabrication of a carbon photocatalyst with abundant carbon defects created by removing the nitrogen atoms from a N-doped precursor. The active defects bond with water molecules during the photocatalytic reaction, which then work as oxidation sites for O₂ generation. We also demonstrate an accessible strategy to produce more defects to observably enhance the photocatalytic activity (around 10 times) as well as to select between the 2-electron/2-electron and the 4-electron pathway water splitting. The synthesized photocatalyst is efficient in photocatalytic visible-light overall water splitting with an optimum H₂ and O₂ production of 2.54 and 1.25 μmol h⁻¹, respectively. Moreover, the quantum efficiency and solar to hydrogen (STH) efficiency were measured to be 2.04% for wavelength λ = 420 ± 20 nm and 0.1% using AM 1.5 G, respectively.

通过光催化剂将水分解产生的氢气是一种最终的清洁和可再生能源策略。近期的发展表明，碳基材料具有高活性，高稳定性，低成本，易于制造和结构多样等特点，因此在可见光下可作为整体水分解的光催化剂。但是，对碳基光催化剂的工作机理仍然缺乏系统的研究和深入的认识。本文中，我们展示了具有大量碳缺陷的碳光催化剂的制备，该碳缺陷是通过从N掺杂的前体中除去氮原子而产生的。活性缺陷在光催化反应过程中与水分子结合，然后充当O _2的氧化位一代。我们还演示了一种可产生更多缺陷的策略，以显着提高光催化活性（约10倍），并在2-电子/ 2-电子和4-电子途径的水分解之间进行选择。合成的光催化剂在光催化可见光总水分解方面是有效的，其最佳H ₂和O ₂产生分别为2.54和1.25μmolh ^-1。此外，使用AM 1.5 G测得的波长λ= 420±20 nm的量子效率和太阳至氢（STH）效率分别为2.04％和0.1％。