Above-Room-Temperature Strong Ferromagnetism in 2D MnB Nanosheet.

Two-dimensional (2D) room-temperature (RT) ferromagnetic materials have amassed considerable interest in the field of fundamental physics for applications in next-generation spintronic devices owing to their physical properties. However, realizing strong RT ferromagnetism and a high Curie temperature (TC) in these 2D magnetic materials remains challenging. Herein, we develop a 2D MnB nanosheet for known 2D ferromagnets that demonstrates strong RT ferromagnetism and a record-high above-RT TC of ∼585.9 K. Through magnetic force microscopy, clear evidence of ferromagnetic behavior is observed at room temperature. Structural characterization and density functional theory calculations further reveal that (i) after exfoliation of bulk, -OH functional groups were introduced in addition to Mn-B bonds being formed, which increases MnB nanosheet TC to 585.9 K and (ii) the d3↑ spin configuration of Mn mainly contributed to the magnetic moment of MnB, and the hybridization between the dxz (dyz) and dz2 orbitals of the Mn atom provides a large contribution to magnetic anisotropy, which stabilizes the magnetic property of MnB. Our findings establish a strong experimental foundation for 2D MnB nanosheets as ideal materials for the construction of spintronic devices.

Construction of PCN-222 and Atomically Thin 2D CNs Van Der Waals Heterojunction for Enhanced Visible Light Photocatalytic Hydrogen Production.

Atomically thin two-dimensional (2D) CN sheets have attracted extensive attention in the field of photocatalysis because of their shorter diffusion path of photogenerated carriers and abundant surface reaction sites than bulk CN. However, 2D CNs still exhibit poor visible-light photocatalytic activity because of a strong quantum size effect. Here, PCN-222/CNs vdWHs were successfully constructed using the electrostatic self-assembly method. The results showed that PCN-222/CNs vdWHs with 1 wt.% PCN-222 enhanced the absorption range of CNs from 420 to 438 nm, which improved the absorption capacity of visible light. Additionally, the hydrogen production rate of 1 wt.% PCN-222/CNs is four times that of the pristine 2D CNs. This study provides a simple and effective strategy for 2D CN-based photocatalysts to promote visible light absorption.