Graphene-based electrocatalytic materials are potential low-cost electrocatalysts for the oxygen evolution reaction (OER). However, substantial overpotentials above thermodynamic requirements limit their efficiency and stability in OER-related energy conversion and storage technologies. Here, we embedded CrN crystals into graphene and in situ electrochemically oxidized them to construct graphene materials with encapsulated Cr⁶⁺ ions (Cr⁶⁺@G). These Cr⁶⁺@G materials exhibit the lowest OER overpotential of 197 mV at 10 mA cm⁻² and excellent stability over 200 h at a high current density of about 120 mA cm⁻² in an alkaline electrolyte. Spectroscopic and computational studies confirm a stable ion coordination environment significantly benefiting the downshift of the graphene Fermi level via hybridization of C p orbitals with d orbitals of Cr⁶⁺ ions that enhances the OER activity and stability.

中文翻译：

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使用轨道杂交策略释放石墨烯对水氧化的潜力†

石墨烯基电催化材料是用于氧释放反应（OER）的潜在低成本电催化剂。然而，超过热力学要求的大量超电势限制了它们在与OER相关的能量转换和存储技术中的效率和稳定性。在这里，我们将CrN晶体嵌入石墨烯中，并对其进行原位电化学氧化，以构建具有封装的Cr ⁶⁺离子（Cr ⁶⁺ @G）的石墨烯材料。这些Cr ⁶⁺ @G材料在10 mA cm ^-2时表现出最低的OER过电势，为197 mV，并且在约120 mA cm ^-2的高电流密度下，在200小时内具有出色的稳定性。在碱性电解液中。光谱和计算研究证实，稳定的离子配位环境通过Cp轨道与d ⁶ Cr离子的d轨道的杂交显着受益于石墨烯费米能级的^下移，从而增强了OER活性和稳定性。