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Highlights: A unique atomic dispersed hetero-pair was successfully synthesized, consisting of Mo-Fe di-atoms anchored on N-doped carbon carrier. This strategy breaks the linear scaling relationships of electrocatalytic CO2 reduction by simultaneously regulating the *COOH adsorption energy and *CO desorption energy. The as-prepared MoFe–N–C exhibits excellent performance for CO2RR to CO with a high turnover frequency (TOF) of 3336.21 h−1, CO Faradaic efficiency (FECO) of 95.96% at − 0.60 V (versus RHE) and outstanding stability. Electrochemical carbon dioxide reduction reaction (CO2RR) involves a variety of intermediates with highly correlated reaction and ad-desorption energies, hindering optimization of the catalytic activity. For example, increasing the binding of the *COOH to the active site will generally increase the *CO desorption energy. Breaking this relationship may be expected to dramatically improve the intrinsic activity of CO2RR, but remains an unsolved challenge. Herein, we addressed this conundrum by constructing a unique atomic dispersed hetero-pair consisting of Mo-Fe di-atoms anchored on N-doped carbon carrier. This system shows an unprecedented CO2RR intrinsic activity with TOF of 3336 h−1, high selectivity toward CO production, Faradaic efficiency of 95.96% at − 0.60 V and excellent stability. Theoretical calculations show that the Mo-Fe diatomic sites increased the *COOH intermediate adsorption energy by bridging adsorption of *COOH intermediates. At the same time, d-d orbital coupling in the Mo-Fe di-atom results in electron delocalization and facilitates desorption of *CO intermediates. Thus, the undesirable correlation between these steps is broken. This work provides a promising approach, specifically the use of di-atoms, for breaking unfavorable relationships based on understanding of the catalytic mechanisms at the atomic scale. [ABSTRACT FROM AUTHOR]

Electrochemical carbon dioxide reduction reaction (CO 2 RR) involves a variety of intermediates with highly correlated reaction and ad-desorption energies, hindering optimization of the catalytic activity. For example, increasing the binding of the *COOH to the active site will generally increase the *CO desorption energy. Breaking this relationship may be expected to dramatically improve the intrinsic activity of CO 2 RR, but remains an unsolved challenge. Herein, we addressed this conundrum by constructing a unique atomic dispersed hetero-pair consisting of Mo-Fe di-atoms anchored on N-doped carbon carrier. This system shows an unprecedented CO 2 RR intrinsic activity with TOF of 3336 h -1 , high selectivity toward CO production, Faradaic efficiency of 95.96% at - 0.60 V and excellent stability. Theoretical calculations show that the Mo-Fe diatomic sites increased the *COOH intermediate adsorption energy by bridging adsorption of *COOH intermediates. At the same time, d-d orbital coupling in the Mo-Fe di-atom results in electron delocalization and facilitates desorption of *CO intermediates. Thus, the undesirable correlation between these steps is broken. This work provides a promising approach, specifically the use of di-atoms, for breaking unfavorable relationships based on understanding of the catalytic mechanisms at the atomic scale., (© 2023. The Author(s).)

Nb 2 CT x , an emerging type of MXene, should be a promising electromagnetic wave (EMW) absorbing material to overcome the EMW pollution nowadays due to its unique layered structure and extremely thin monolayer thickness, but was lack of systematic study till now. Meanwhile, Nb 2 CT x nanosheets obtained upon HF etching of Nb 2 AlC MAX was unfortunately found with limited absorption performance due to its mainly dielectric loss mechanism herein. Therefore, the Nb 2 CT x nanosheets were further treated with solvothermal strategy in various solvents. As a result, the absorption performance of the as-treated Nb 2 CT x nanosheets could be significantly improved, while the ones in ethanol showed much more superior absorption capability, especially in the low-frequency band (2.0-4.0 GHz). The minimum reflection loss value could reach -52.2 dB at 3.93 GHz with the thickness of only 2.90 mm, indicating more than 99.999% EMW was absorbed. These should be due to the multi-loss mechanism including dielectric, interfacial, and multiple reflection ones resulting from the enlarged interlayer spacing, and increased surface functional groups on the Nb 2 CT x nanosheets upon the ethanol-based solvothermal treatment., (Copyright © 2018 Elsevier Inc. All rights reserved.)