Single vs double atom catalyst for N ₂ activation in nitrogen reduction reaction: A DFT perspective

Journal Article · 19 January 2020 · EcoMat

DOI: https://doi.org/10.1002/eom2.12014 · OSTI ID:1592491

Qian, Yumin ^[1]; Liu, Yuanyue ^[2]; Zhao, Yu ^[3]; Zhang, Xiaohong ^[3]; Yu, Guihua  ^[2]

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1. Institute of Functional Nano &, Soft Materials (FUNSOM) Jiangsu Key Laboratory for Carbon‐Based Functional Materials &, Devices, Soochow University Suzhou Jiangsu China, Materials Science and Engineering Program and Department of Mechanical Engineering The University of Texas at Austin Austin Texas
2. Materials Science and Engineering Program and Department of Mechanical Engineering The University of Texas at Austin Austin Texas
3. Institute of Functional Nano &, Soft Materials (FUNSOM) Jiangsu Key Laboratory for Carbon‐Based Functional Materials &, Devices, Soochow University Suzhou Jiangsu China

Abstract Ammonia synthesis through electrochemical reduction of nitrogen molecules is a promising strategy to significantly reduce the energy consumption in traditional industrial process. Detailed mechanism study of multistep complex nitrogen reduction reaction is prerequisite for the design of highly efficient catalyst. Stable atomically dispersed catalyst with unique geometric and electronic structure is suitable for the mechanism clarification of such a complex reaction. In this study, d ‐block transition‐metal (TM) anchored C ₂ N single layer catalyst is investigated by the density functional theory (DFT) calculation. Both single TM‐anchored single atom catalyst (SAC) and double TM‐anchored double atom catalyst (DAC) exhibit good thermodynamic stability in atomically dispersed catalyst. In the case of SACs, IVB metals (Ti, Zr, Hf) exhibit the highest reactivity and lowest overpotential. While in the case of DACs, Cr─Cr system leads to the NH ₃ formation, but V─V system leads to the N ₂ H ₄ formation. The SACs show much lower overpotential and stronger activation of N ₂ molecule than the DACs due to the different activation mechanisms: traditional σ ‐donation/ π ‐backdonation N ₂ activation mechanism is found in SACs, while a new π ‐donation/π‐backdonation N ₂ activation mechanism is found in the DACs. The present work demonstrates that the different catalytic effect for NRR between SAC and DAC and their corresponding electronic structure origin, which gives more insight into the single atom catalyst. image

• Sponsoring Organization: USDOE
• Grant/Contract Number: DE‐SC0019019
• OSTI ID: 1592491
• Alternate ID(s): OSTI ID: 1592492
• Journal Information: EcoMat, Journal Name: EcoMat Vol. 2 Journal Issue: 1; ISSN 2567-3173
• Publisher: Wiley Blackwell (John Wiley & Sons)Copyright Statement
• Country of Publication: China
• Language: English