Solid-Phase Synthesis Of Two-Dimensional Non-layered Nanomaterials And Their Applications

Since the discovery of graphene,the excellent electrical conductivity,thermal conductivity and good transparency of two-dimensional materials have made them widely used in electronic,mechanical and optical fields,which has also caused researchers to study other two-dimensional nanomaterials.Driven by the novel characteristics and broad application prospects of two-dimensional nanomaterials,many methods for preparing two-dimensional nanomaterials,including mechanical cleavage,liquid exfoliation,ion-intercalation and exfoliation,have been developed.various 2D materials have been successfully obtained.However,the currently used preparation methods are only applicable to materials which are layered structures themselves,such as graphene,boron nitride,molybdenum disulfide,etc.,and it is difficult to generalize to other non-layered material systems,thus greatly limiting the type of two-dimensional materials.Based on the above considerations,this paper proposes a solid-phase reaction strategy.By means of the characteristics of solid-phase reaction mass transfer,the reaction is preferentially carried out on the surface.Two-dimensional non-layered molybdenum dioxide nanosheets and two-dimensional non-layered copper nanosheets are successfully prepared by controlling the reaction time,and their applications in surface enhanced Raman scattering(SERS)detection and electrocatalytic carbon dioxide reduction were investigated.This Provides a new idea for the construction of 2D materials.The main contents are as follows:(1)Preparation of two-dimensional M0O2 nanosheets by solid-phase reaction and its preparation mechanism.Two-dimensional M0O2 nanosheets were successfully prepared by solid-phase reaction.It was proved by various characterization methods that two-dimensional non-layered MoO2 nanosheets with high crystallinity and ultra-thin thickness(about 0.7 nm)were prepared.Compared with the reported methods for preparing two-dimensional non-layered nanomaterials,the solid-phase reaction method has the advantages of simplicity,novelty and uniqueness,short synthetic route,easy control of reaction process and high safety factor.(2)Two-dimensional MoO2 nanosheets used for surface-enhanced Raman scattering.In this work,we used the successfully prepared two-dimensional MoO2 nanosheets by solid-phase reaction method for testing.Ultraviolet-visible spectroscopic characterization showed that the two-dimensional MoO2 nanosheets exhibited fairly strong and clear plasma resonance absorption peaks at 860 nm,and the LSPR peaks remained stable under acid-base corrosion,high temperature heat treatment and long-term irradiation conditions.Then,these two-dimensional MoO2 nanosheets were used as substrates for surface enhanced Raman scattering and their properties were tested.The detection results of typical dye molecule Rhodamine 6G(R6G)showed that the ultralow limit of detection(LOD)was 10-7 M and the maximum enhancement factor(EF)was 1.7×104.which had a very good detection effect.(3)Preparation of two-dimensional copper nanosheets by solid-phase reaction and its application in electrocatalysis carbon dioxide reduction.In order to prove the universality of solid-phase reaction method for preparing two-dimensional non-layered nanosheets,we also prepared copper nanosheets.The characterization showed that two-dimensional non-layered copper nanosheets with high crystallinity and thin thickness were prepared.Then the samples were applied to electrocatalysis carbon dioxide reduction.The results show that the prepared samples have potential application for electrocatalysis carbon dioxide reduction.It is expected to solve the problem of preparation of copper-based nanomaterials in electrocatalysis carbon dioxide reduction,and provide more theoretical and experimental basis for the development of green,feasible,low-cost,stable and efficient electrocatalysts.