Depositing a cocatalyst has proven to be an important strategy for improving the photoelectrochemical (PEC) water-splitting efficiency of photoanodes. In this study, Ni(OH)₂ quantum dots (Ni(OH)₂ QDs) were deposited in situ onto an α-Fe₂O₃ photoanode via a chelation-mediated hydrolysis method. The photocurrent density of the Ni(OH)₂ QDs/α-Fe₂O₃ photoanode reached 1.93 mA(cm⁻² at 1.23 V vs. RHE, which is 3.5 times that of α-Fe₂O₃, and an onset potential with a negative shift of ca. 100 mV was achieved. More importantly, the Ni(OH)₂ QDs exhibited excellent stability in maintaining PEC water oxidation at a high current density, which is attributed to the ultra-small crystalline size, allowing for the rapid acceptance of holes from α-Fe₂O₃ to Ni(OH)₂ QDs, formation of active sites for water oxidation, and hole transfer from the active sites to water molecules. Further (photo)electrochemical analysis suggests that Ni(OH)₂ QDs not only provide maximal active sites for water oxidation but also suppress charge recombination by passivating the surface states of α-Fe₂O₃, thereby significantly enhancing the water oxidation kinetics over the α-Fe₂O₃ surface.

沉积助催化剂已被证明是提高光阳极光电化学（PEC）水分解效率的重要策略。在这项研究中，Ni(OH) ₂量子点（Ni(OH) ₂ QDs）通过螯合介导的水解方法原位沉积在α-Fe ₂ O _{3 光}阳极上。Ni(OH) ₂ QDs/α-Fe ₂ O _{3 光}阳极的光电流密度达到1.93 mA(cm ^-2 at 1.23 V vs. RHE，是α-Fe ₂ O _{3 的}3.5倍，起始电位负移约。达到了 100 mV。更重要的是，Ni(OH) ₂ QDs 在高电流密度下保持 PEC 水氧化方面表现出优异的稳定性，这归因于超小的晶体尺寸，允许快速接受从 α-Fe ₂ O ₃到Ni(OH) ₂ QD，水氧化活性位点的形成，以及空穴从活性位点转移到水分子。进一步的（光）电化学分析表明，Ni(OH) ₂ QDs 不仅为水氧化提供了最大的活性位点，而且还通过钝化 α-Fe ₂ O ₃的表面态来抑制电荷复合，从而显着增强α-Fe ₂ O ₃表面上的水氧化动力学。