Synthesis Of Defect-rich Ni(OH)₂ Nanosheets And Their Electrocatalytic Properties Of N-propylamine

Nitriles are an important class of nitrogen-containing compounds in chemistry and biology.Most of the traditional nitriles synthesis processes require the participation of cyanide or high temperature conditions,so they can not meet the requirements of sustainable development.Electrocatalytic dehydrogenation of primary amines to nitriles provides a clean,simple and effective method for obtaining nitriles,which has great application value in the fields of industry,agriculture,and medicine.However,the conversion process from C-N bond to C?N bond has not been explored in detail.The effective chemisorption of the C-N bond of the primary amines and the subsequent multi-electron transfer reaction will be the key to the conversion of the primary amines to nitriles.Local surface charge density plays a vital role in the adsorption and activation of electrocatalysts.In this work,we used defect engineering to control the surface charge density of the catalyst,and prepared defect-limited Ni(OH)₂ nanosheets,which were used as an electrocatalyst to drive primary amines to be converted to nitriles.The main work are listed as follows:(1)Ni-MOFs ultrathin nanosheets were used as precursor to realize the successful synthesis of defect-limited Ni(OH)₂ nanosheets through in-situ electrochemical topology conversion.The electronic structure of defect-limited Ni(OH)₂ nanosheets were studied by means of synchrotron radiation X-ray absorption fine structure spectrum and X-ray photoelectron spectroscopy,which confirmed the successful introduction of vacancy defects.(2)Electrochemical tests were performed on the oxidation performance of n-propylamine using the prepared defect-limited Ni(OH)₂ nanosheets,and it was found that defect engineering could significantly improve its catalytic performance.Secondly,with in situ FT-IR,we could directly observe that defect-rich Ni(OH)₂ nanosheets driven primary amines to convert to nitriles.The Faraday efficiency of propionitrile at the potential of 1.38V vs.RHE was 96.5%.Finally,through theoretical calculations,we found that the existence of defects could effectively induce the distribution of lean electrons on the catalyst surface,so as to chemically adsorb the lone pair electrons in the N atom to further attack the N-H bond to activate the n-propylamine molecule.Exploring the atomic structure-charge distribution-chemical bond activation process can also provide a reference for the efficient transformation of other chemical products.