Atomscopic of ripple origins for two-dimensional monolayer transition metal dichalcogenides

During the development of ultrathin two-dimensional(2D)materials,the appearance of ripples has been widely observed.However,the formation mechanisms and their influences are still rarely investigated,especially their contributions to the electronic structures and optical properties.To compensate for the knowledge gap,we have carried out comprehensive theoretical studies on the monolayer WSe_(2) with a series of ripple structures from 0 to 12Åin different lattice sizes.The sensitivity of the formation energy,band structures,electronic structures,and optical properties to the ripple structures have been performed systematically for the first time.The formation of ripples in Armchair and zigzag simultaneously are more energetically favorable,leading to more flexible optimizations of the optoelectronic properties.The improved charge-locking effect and extension of absorption ranges indicate the significant role of ripple structures.The spontaneous formation of ripples is associated with orbital rearrangements and structural distortions.This leads to the unique charge carrier correlate inversion between W-5d and Se-4p orbitals,resulting in the pinning of the Fermi level.This work has supplied significant references to understand ultrathin 2D structures and benefit their future developments and applications in high-performance optoelectronic devices.

Neighboring effect in single-atom catalysts for the electrochemical carbon dioxide reduction reaction

Although single-atom catalysts(SACs)have attracted enormous attention for their applications in the electrochemical reduction of CO_(2)(CO_(2)RR)due to their extraordinary catalytic activity and well-defined active centers,neighboring effects and their influence on the electrochemical performance of SACs have not been well investigated.In this review,we present a summary of the neighboring effects on SACs for the CO_(2)RR process,where the surrounding atoms not only induce electronic modulation of the metal atom but also participate in the CO_(2)RR.Both theoretical and experimental studies have pointed out that the neighboring sites of the anchored metal center can provide second active/adsorption locations during the catalytic process,enhancing CO_(2)RR performance tremendously.This review supplies advanced insights into the significant roles and impacts of neighboring effects on the catalytic process,which also benefit the development of advanced SACs to achieve efficient electrocatalysis.