TY - JOUR
T1 - Kinetics and Evolution of Magnetism in Soft-Chemical Synthesis of CrSe2from KCrSe2
AU - Song, Xiaoyu
AU - Schneider, Sarah N.
AU - Cheng, Guangming
AU - Khoury, Jason F.
AU - Jovanovic, Milena
AU - Yao, Nan
AU - Schoop, Leslie M.
N1 - Funding Information:
This work was supported by the Gordon and Betty Moore Foundation through Grant GBMF9064 to L.M.S., the David and Lucile Packard Foundation, the Sloan Foundation, and the Princeton Catalysis Initiative (PCI). Additional support was provided by NSF through the Princeton Center for Complex Materials, a Materials Research Science and Engineering Center DMR-2011750. The authors acknowledge the use of Princeton’s Imaging and Analysis Center, which is partially supported by the Princeton Center for Complex Materials, a National Science Foundation (NSF)-MRSEC program (DMR-2011750), and the use of the Department of Chemistry’s core facility at Princeton University.
Publisher Copyright:
©
PY - 2021/10/26
Y1 - 2021/10/26
N2 - Cation deintercalation with soft-chemical methods provides a route to synthesize new layered compounds with emergent physical and chemical properties that are inaccessible by conventional high-temperature solid-state synthesis methods. One example is CrSe2, a van der Waals (vdW) material that is promising as an air-stable two-dimensional (2D) magnet. Cation deintercalation has rarely been studied mechanistically, and optimized reaction pathways to yield high-quality materials are often poorly understood. In this work, we perform a detailed study of the oxidative deintercalation process of KCrSe2. We prove for the first time using high-resolution scanning transmission electron microscopy (STEM) that even though CrSe2 indeed exists in a true vdW-layered structure, K-intercalated crystalline defects exist in the final product, even when an excess of oxidizing agent was used. We then study the kinetics of the oxidative deintercalation process, showing that it is a zeroth-order reaction with an activation energy of 0.27(6) eV, where the solid-state diffusion of K+ cations in the potassium deintercalation process is the rate-limiting step. Finally, we study the relationship between Cr-Cr distances and the change in magnetic order by tracking how the properties change as a function of varying potassium content due to deintercalation. These data suggest that it might be possible to switch between magnetic states in CrSe2 monolayers by varying its lattice parameters with methods, such as applying strain. Our study also provides a deeper understanding of the cation deintercalation process from a mechanistic perspective that will be helpful for the future development of synthetic methodology that can lead to other new layered materials.
AB - Cation deintercalation with soft-chemical methods provides a route to synthesize new layered compounds with emergent physical and chemical properties that are inaccessible by conventional high-temperature solid-state synthesis methods. One example is CrSe2, a van der Waals (vdW) material that is promising as an air-stable two-dimensional (2D) magnet. Cation deintercalation has rarely been studied mechanistically, and optimized reaction pathways to yield high-quality materials are often poorly understood. In this work, we perform a detailed study of the oxidative deintercalation process of KCrSe2. We prove for the first time using high-resolution scanning transmission electron microscopy (STEM) that even though CrSe2 indeed exists in a true vdW-layered structure, K-intercalated crystalline defects exist in the final product, even when an excess of oxidizing agent was used. We then study the kinetics of the oxidative deintercalation process, showing that it is a zeroth-order reaction with an activation energy of 0.27(6) eV, where the solid-state diffusion of K+ cations in the potassium deintercalation process is the rate-limiting step. Finally, we study the relationship between Cr-Cr distances and the change in magnetic order by tracking how the properties change as a function of varying potassium content due to deintercalation. These data suggest that it might be possible to switch between magnetic states in CrSe2 monolayers by varying its lattice parameters with methods, such as applying strain. Our study also provides a deeper understanding of the cation deintercalation process from a mechanistic perspective that will be helpful for the future development of synthetic methodology that can lead to other new layered materials.
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U2 - 10.1021/acs.chemmater.1c02620
DO - 10.1021/acs.chemmater.1c02620
M3 - Article
AN - SCOPUS:85117529302
SN - 0897-4756
VL - 33
SP - 8070
EP - 8078
JO - Chemistry of Materials
JF - Chemistry of Materials
IS - 20
ER -