| 1 | Spectroscopic investigation of defects mediated oxidization of single-layer MoS_(2)显示文摘Due to the extremely large surface to bulk ratio,the properties of single layer(SL)MoS_(2)are largely determined by its interaction with environment.One critical interaction process that has been intensively investigated is the oxidation process of MoS_(2).Despite numerous previous explorations,the detailed mechanism regarding how MoS_(2)reacts with oxygen is still not well understood.In this work,we systematically investigate the impact of intrinsic and pre-created defects on the oxidation process of SL MoS_(2).For pristine SL MoS_(2),the oxidation is found to initiate near point defects and grain boundaries,leading to the formation of triangle pits in the basal plane and cracks near the grain boundaries.The pre-created defects introduced by ion irradiation are found to serve as the oxidation center,resulting in a more uniform oxidation process.The oxidation is found to introduce p-type doping in the SL MoS_(2),leading to the blue shift of Raman and photoluminescence(PL)spectra.The shift is found to be more for the region near the grain boundary and for the samples with more pre-created defects.Our results suggest that the presence of defects can strongly promote the oxidation reaction of SL MoS_(2)in ambient condition,which significantly affects the stability and functionality of materials. | HE ZuYun GUO Zheng ZHONG Xiao CHEN XiaoFei XUE JianMing WANG XinWei CHEN Yan | 2021 | Science China(Technological Sciences)2021，64，3： | 1 |
| 2 | Modulating surface oxygen species via facet engineering for efficient conversion of nitrate to ammonia显示文摘Electrochemical reduction of nitrate,a common pollutant in aquatic environment,to valuable ammonia(NO3-RR) using renewably-sourced electricity has attracted widespread interests,with past efforts mainly focused on designing electrocatalysts with high activity and selectivity.The detailed correlation between catalyst properties and NO3-RR kinetics,nevertheless,is still not fully understood.In this work,we modulate the surface oxygen species of Cu_(2)O via facet engineering,and systematically study the impact of these oxygen species on the NO_(3)^(-)RR activity.Combining advanced spectroscopic techniques,densi ty fu n ctional theory calculations and molecular dynamics simulations,we find that while oxygen vacancies on Cu_(2)O(111) surface promote the adsorption of reactants and reaction intermediates,hydroxyl groups effectively inhibit the side reaction of hydrogen evolution and facilitate the hydrogenation process of NO3-RR.These two effects work in concert to render Cu_(2)O(111) facet the highest NO3-RR activity relative to those from other facets.Our study provides critical insights into the synergistic effect of exposed facets and surface oxygen species on heterogeneous catalysis,and offers a generalizable,facet engineeringbased strategy for improving the performance of a variety of electrocatalysts important for renewable energy conversion. | Wenye Zhong Zhiheng Gong Zuyun He Nian Zhang Xiongwu Kang Xianwen Mao Yan Chen | 2023 | Journal of Energy Chemistry2023，，3： | 0 |
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