通过p-p轨道耦合和孔隙工程提高p-嵌段单原子催化剂的酸性氧还原活性,Small Structures

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通过p-p轨道耦合和孔隙工程提高p-嵌段单原子催化剂的酸性氧还原活性
Small Structures ( IF 13.9 ) Pub Date : 2023-04-05 , DOI: 10.1002/sstr.202300007
Hu Wang ₁ , Yongjian Zhao ₁ , Jun Li ₁ , Xiaosha Wang ₁ , Murong Huang ₁ , Lei Zhang ₁ , Chenyang Zhao ₁

Affiliation

原子分散的主族元素单原子催化剂（SAC）最近在电催化领域引起了越来越多的关注。然而，由于配位环境欠佳、传质有限和活性位点暴露，它们在酸性氧还原反应（ORR）中的性能仍然不能令人满意。在此，通过双熔盐介导的软模板法制备了一系列具有分级孔结构的p-嵌段Sn SAC。通过刻意调节孔结构，获得了具有N/O配位的高度暴露的Sn活性位点，这赋予SnN ₃ O-50优异的ORR性能，特别是在酸性介质中。_{SnN 3}的半波电势O-50 高达 0.816 V，10 000 次电位循环后仅损失 15 mV。_{此外，使用SnN 3} O-50作为阴极组装的燃料电池和锌空气电池的峰值功率密度分别达到502和173.5 mW cm ^-2，具有巨大的实际应用潜力。密度泛函理论（DFT）计算表明，Sn的N/O配位引起5 p电子的局域化，从而导致与O _2的p轨道强耦合。同时，缺陷的存在协同调节反应中间体的吸附，从而优化四个连续ORR步骤的自由能。

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Boosting the Acidic Oxygen Reduction Activity of p-Block Single-Atomic Catalyst via p–p Orbital Coupling and Pore Engineering

Atomically dispersed main group element single-atom catalysts (SACs) have recently attracted increasing attention in electrocatalysis. However, their performances in acidic oxygen reduction reaction (ORR) remain unsatisfactory owing to the suboptimal coordination environment, limited mass transfer, and active site exposure. Herein, a series of p-block Sn SACs with hierarchical pore structures are prepared by a dual melting salt-mediated soft template method. By deliberately regulating the pore structures, highly exposed Sn active sites with N/O coordination are obtained, which endow SnN₃O-50 with exceptional ORR performances, especially in acidic medium. The half-wave potential of SnN₃O-50 is up to 0.816 V, with a loss of only 15 mV after 10 000 potential cycles. Furthermore, the peak power densities of the fuel cell and zinc–air battery assembled using SnN₃O-50 as cathodes reach 502 and 173.5 mW cm⁻², respectively, demonstrating great potential for practical applications. Density functional theory (DFT) calculations reveal that the N/O coordination of Sn induces localization of 5p electrons, which leads to strong coupling with the p orbit of O₂. Meanwhile, the presence of defects synergistically regulates the adsorption of reaction intermediates, thereby optimizing the free energy of the four successive ORR steps.

更新日期：2023-04-05

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