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DOE OSTI · 2965082

Well-Defined Iron Sites in Crystalline Carbon Nitride

Genoux, Alexandre [Yale University, New Haven, CT (United States)]·Pauly, Magnus [North Carolina State University, Raleigh, NC (United States)]·Rooney, Conor L. [Yale University, New Haven, CT (United States)] (ORCID:000000017058568X)·Choi, Chungseok [Yale University, New Haven, CT (United States)]·Shang, Bo [Yale University, New Haven, CT (United States)] (ORCID:0000000222946062)·McGuigan, Scott [North Carolina State University, Raleigh, NC (United States)] (ORCID:0000000295540151)·Fataftah, Majed S. [Yale University, New Haven, CT (United States)]·Kayser, Yves [Max Planck Institute for Chemical Energy Conversion, Mülheim an der Ruhr (Germany)]·Suhr, Simon C. B. [Yale University, New Haven, CT (United States)]·DeBeer, Serena [Max Planck Institute for Chemical Energy Conversion, Mülheim an der Ruhr (Germany)] (ORCID:0000000251963400)·Wang, Hailiang [Yale University, New Haven, CT (United States)] (ORCID:0000000344092034)·Maggard, Paul A. [North Carolina State University, Raleigh, NC (United States)] (ORCID:0000000239091590)·Holland, Patrick L. [Yale University, New Haven, CT (United States)] (ORCID:0000000228832031)
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Abstract

Carbon nitride materials can be hosts for transition metal sites, but Mössbauer studies on iron complexes in carbon nitrides have always shown a mixture of environments and oxidation states. Here we describe the synthesis and characterization of a crystalline carbon nitride with stoichiometric iron sites that all have the same environment. The material (formula C 6 N 9 H 2 Fe 0.4 Li 1.2 Cl, abbreviated PTI/FeCl 2 ) is derived from reacting poly(triazine imide)·LiCl (PTI/LiCl) with a low-melting FeCl 2 /KCl flux, followed by anaerobic rinsing with methanol. X-ray diffraction, X-ray absorption and Mössbauer spectroscopies, and SQUID magnetometry indicate that there are tetrahedral high-spin iron(II) sites throughout the material, all having the same geometry. As a result, the material is active for electrocatalytic nitrate reduction to ammonia, with a production rate of ca. 0.1 mmol cm –2 h –1 and Faradaic efficiency of ca. 80% at −0.80 V vs RHE.

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Genoux, Alexandre [Yale University, New Haven, CT (United States)], Pauly, Magnus [North Carolina State University, Raleigh, NC (United States)], Rooney, Conor L. [Yale University, New Haven, CT (United States)] (ORCID:000000017058568X), Choi, Chungseok [Yale University, New Haven, CT (United States)], Shang, Bo [Yale University, New Haven, CT (United States)] (ORCID:0000000222946062), McGuigan, Scott [North Carolina State University, Raleigh, NC (United States)] (ORCID:0000000295540151), Fataftah, Majed S. [Yale University, New Haven, CT (United States)], Kayser, Yves [Max Planck Institute for Chemical Energy Conversion, Mülheim an der Ruhr (Germany)], Suhr, Simon C. B. [Yale University, New Haven, CT (United States)], DeBeer, Serena [Max Planck Institute for Chemical Energy Conversion, Mülheim an der Ruhr (Germany)] (ORCID:0000000251963400), Wang, Hailiang [Yale University, New Haven, CT (United States)] (ORCID:0000000344092034), Maggard, Paul A. [North Carolina State University, Raleigh, NC (United States)] (ORCID:0000000239091590), Holland, Patrick L. [Yale University, New Haven, CT (United States)] (ORCID:0000000228832031). 2023-09-13. Well-Defined Iron Sites in Crystalline Carbon Nitride. https://doi.org/10.1021/jacs.3c05417

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