Elucidating how the local strain environment of single atoms affects their impact on a sluggish acidic oxygen reduction reaction (ORR) is important for the design and construction of highly active electrocatalysts. Here, we report that the atomic strain geometry of Fe single sites is exclusively regulated by the communicative effects of dual atoms. Theoretical analysis reveals that Fe-Ru dual atoms in a moderate strain environment achieve the lowest Gibbs free energy barrier during an ORR. Impressively, FeRu-N-C with an FeRuN 8 moiety exhibits the highest acidic ORR performance, with a half-wave potential ( E 1/2 ) of 0.860 V and only a 17-mV loss in E 1/2 after 50,000 potential cycles. Operando characterization and electronic configuration analysis demonstrate that moderately strained Fe sites promote hydrogenation desorption of (oxy-)hydroxyl by enabling more electrons to occupy antibonding orbitals. This study describes a promising way of investigating high-performance single-atom-based catalysts by tailoring the atomic strain environment.
Liu Minmin,Yang Liting,Wu Zhengchen,Chen Guanyu,Wang Xiangyu,Yang Xiaofen,Liang Guisheng,Che Renchao
Periodically atomic displacement in two-dimensional (2D) ripple texturing offers a promising route for selective modulation of local potential, crucial for advanced electronic engineering. However, in 2D transition metal carbonitrides (MXenes), the construction and regulation of atomic ripples to control electronic properties meet substantial challenges due to the difficulty in tailoring homogeneous deformation. Here, we propose a competition strategy that leverages configurational entropy and surface termination to controllably modulate the atomic ripple structure within Nb 2 CTe x -based Mxenes. This chemical disorder releases the local in-plane strain induced by termination atoms with large ionic radii, thus enabling the regulation of out-of-plane atomic displacement. The deliberate design of the ripple structure regulates the dielectric relaxation time of the microscopic dipole in the electric field. Consequently, high-entropy MXenes deliver strong intensity of microwave absorption (−41.12 dB) and an absorption bandwidth of nearly 10 GHz, covering the S-, C-, and X-bands. This study establishes the relationship between atomic ripple structure, atomic strain, polarization relaxation, and dielectric properties, providing guidance for designing advanced MXenes materials for various applications.
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