Co2P/CoP heterostructures with significantly enhanced performance in electrocatalytic hydrogen evolution reaction: Synthesis and electron redistribution mechanism
Co2P/CoP heterostructures with significantly enhanced performance in electrocatalytic hydrogen evolution reaction: Synthesis and electron redistribution mechanism
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DOI：
10.1007/s12274-023-6228-3
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发表时间：
2023-10
期刊：
影响因子：
9.9
通讯作者：
Baoshan Liu;Boan Zhong;Feng Li;Jing Liu;Liping Zhao;Peng Zhang;Lian Gao
中科院分区：
文献类型：
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作者：
Baoshan Liu;Boan Zhong;Feng Li;Jing Liu;Liping Zhao;Peng Zhang;Lian Gao
异质结构通常被用来调节两种催化剂的电子状态，从而在碱性析氢反应（HER）中实现高性能。已经提出了各种机制的异质结构催化剂，但有待进一步的认可。在本文中，成功地制备了由Co2 P和CoP组成的异质结构，相对于端员具有显著增强的HER催化活性。紫外光电子能谱（UPS）和X射线光电子能谱（XPS）研究表明，Co2 P/CoP界面内建电场的强电子耦合作用有效地促进了CoP向Co2 P的自驱动电子转移和Co2 P中P位上电子的积累，原位电化学阻抗谱（EIS）和毒物实验证实了H* 的Heyrovsky台阶电负性P位点上的中间体耗尽以及金属和P两者对Co2 P/CoP中的反应性的贡献。密度泛函理论（DFT）计算表明，异质结界面的电子结构显著削弱了Co2 P/CoP中P位的氢吸附自由能（ΔGH* ads），使其接近于零.我们还提出了一个电子再分配策略的异质结构，激活多路机制和生产更活跃的网站。该作用机制有望进一步扩展到其他过渡金属化合物以获得高效HER活性。
Heterostructures are often constructed to modulate the electronic states of the two catalysts, achieving high-performance in alkaline hydrogen evolution reaction (HER). Various mechanisms have been proposed for the heterostructural catalysts, which however awaits further approvement. Herein, a heterostructure composed of Co2P and CoP was successfully prepared with significantly enhanced HER catalytic activity relative to the endmembers. The ultraviolet photoelectron spectroscopy (UPS) and X-ray photoelectron spectroscopy (XPS) revealed the effective promotion of the self-driven transferring of electrons from CoP to Co2P and the accumulation of electrons on the P sites in Co2P due to the strong electronic coupling of built-in electric field in the Co2P/CoP interface.In situelectrochemical impedance spectroscopy (EIS) and poison experiments confirmed the Heyrovsky step of H* intermediate depleting on electronegative P sites and contributions of both metal and P to the reactivity in the Co2P/CoP. Density functional theory (DFT) calculations clarify that the electronic structure at interface of the heterojunction significantly weakens the hydrogen adsorption free energy (ΔGH* ads) of P site in Co2P/CoP to near zero. We also propose an electronic redistribution strategy for heterostructures that activates the multiple routes mechanism and production of more active sites. The working mechanism is expected to be further extended to other transition metal compounds for efficient HER activity.