The design of a photoanode with a bridging strategy that can enhance the charge injection and transport in a heterojunction can be an efficient approach to separate the photogenerated charge carriers and enhance the water oxidation kinetics. Aiming at such issues, herein we propose a BiVO₄/GQDs/CoSn-LDH (layered double hydroxide) photoanode, which leads to the formation of a p–n heterojunction with bridged graphene quantum dots (GQDs) to accelerate the photoelectrochemical (PEC) performance. The BiVO₄/GQDs/CoSn-LDH photoanode exhibits a maximum photocurrent density of 4.15 mA/cm², which is ∼3-fold higher than for the pristine BiVO₄ photoanode with an ∼250 mV cathodic shift in the onset potential. A faradaic yield of ∼91% confirms that the obtained photocurrent is mainly due to water oxidation. A mechanistic study based on the electrochemical impedance (EIS), charge separation, and charge injection efficacy measurements reveals that the introduction of GQDs between BiVO₄ and CoSn-LDH provides a continuous conducting network to extract holes from the BiVO₄ surface and efficiently inject into the CoSn-LDH surface for the water oxidation reaction.

中文翻译：

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使用石墨烯量子点增强水氧化动力学的 BiVO4/CoSn 层状双氢氧化物 p-n 异质结方法中电荷提取/注入的界面桥接策略

具有桥接策略的光阳极设计可以增强异质结中的电荷注入和传输，是分离光生电荷载流子和增强水氧化动力学的有效方法。针对这些问题，我们在本文中提出了一种 BiVO ₄ /GQDs/CoSn-LDH（层状双氢氧化物）光阳极，它导致形成具有桥接石墨烯量子点（GQD）的 ap-n 异质结以加速光电化学（PEC）性能. BiVO ₄ /GQDs/CoSn-LDH 光阳极的最大光电流密度为 4.15 mA/cm ²，是原始 BiVO _{4 的}约 3 倍光阳极的起始电位具有~250 mV的阴极位移。约 91% 的法拉第产率证实获得的光电流主要是由于水氧化。基于电化学阻抗 (EIS)、电荷分离和电荷注入效率测量的机理研究表明，在 BiVO ₄和 CoSn-LDH之间引入 GQD提供了一个连续的导电网络，以从 BiVO ₄表面提取空穴并有效注入用于水氧化反应的 CoSn-LDH 表面。