Uncovering The Impact Of Anionic Defects On Catalytic Activity Of Non-noble Metal Based Catalysts

Because of structural diversity and earth-abundant characteristic,non-noble metal catalysts have attracted great attentions to replace noble-metal catalysts such as Pt,Ir O2.The catalytic performance of non-noble metal catalysts nevertheless requires further enhancement for practical applications.Anion defect engineering,as a effective way to improve the inherent activity of materials,is widely used to improve the catalytic activity of materials.In this work,we use transition metal hydroxide Ni(OH)2,high-entropy oxides Co Ni Cu Zn Mg O and monolayer WSe2 as model materials.Defect with different types and density were generated into the catalyst by using plasma treatment,entropy stabilization strategy,and ion irradiation techniques.The catalytic performance of the obtained material is systematically compared.The main research contents of this paper are as follows:1.The use of anion defect engineer enhances the glucose detection performance of Ni(OH)2.Ni(OH)2 nanosheets were synthesized by electrochemical deposition method,and different concentrations of oxygen defects were introduced into the Ni(OH)2 nanosheets by Ar plasma treatment.Ni(OH)2,which is rich in oxygen deficiency,shows higher sensitivity and wider linear response range for glucose monitoring.The results of in-situ Raman spectroscopy showed that the existence of oxygen defects promoted the deprotonation reaction of Ni(OH)2,and the Ni OOH intermediate formed strongly promoted the oxidation of glucose.This work clarifies the important role of defects in improving the glucose detection performance of transition metal hydroxides,and proves that anion defect engineering can be used to improve the performance of sensors.2.The multi-element high-entropy oxides Co Ni Cu Zn Mg O was selected as the model material system,and the impact of disorder on the OER activity of Co Ni Cu Zn Mg O material was systematically studied.High-entropy ceramic materials with different levels of disorder are constructed by controlling the material calcination temperatures.As the degree of disorder increases,Co and Ni show a lower valence state,and the concentration of oxygen vacancies also increases.The p H dependence test shows that the OER reaction in Co Ni Cu Zn Mg O with high entropy is a decoupled proton and electron transfer process.Our results show that the entropy increase will introduce oxygen vacancies in the high-entropy ceramic oxide,thereby improving the OER performance of the material.3.We chose monolayer WSe2 as the model material to explored the effects of strain,defects,and oxygen absorption on the catalytic performance of HER by heat treatment.The short-time heat treatment improves the HER catalytic performance of WSe2,which is attributed to the reduction of the free energy of hydrogen adsorption by the tensile stress.In-situ Raman test of the oxygen absorption of the monolayer WSe2 confirms that during the oxygen adsorption process,electrons will be transferred from the monolayer WSe2 to oxygen atoms,resulting in p-type doping.And low-energy ions irradiation is used to control defects on the surface of the material,which introduced Se vacancies in the material.This work can help guide the followup study on the defect regulation of transition metal disulfides by ion irradiation technology.