Hydrophobic treatment of the catalyst surfaces can suppress the competitive hydrogen evolution reaction(HER) during the nitrogen reduction reaction(NRR).In this work,the surface of Ti_(3)C_(2)Ti_(x) MXene is modified ...Hydrophobic treatment of the catalyst surfaces can suppress the competitive hydrogen evolution reaction(HER) during the nitrogen reduction reaction(NRR).In this work,the surface of Ti_(3)C_(2)Ti_(x) MXene is modified by cetyltrimethylammonium bromide(CTAB) and trimethoxy(3,3,4,4,5,5,6,6,7,7,8,8,8-trideca fluorooctyl) silane(FOTS) to increase the hydrophobicity of MXenes.The ammonia(NH_(3)) production rate and faradaic efficiency(FE) are improved from 37.62 to 54.01 μg h^(-1)mg_(cat)^(-1).and 5.5% to 18.1% at-0.7 V vs.RHE,respectively after surface modification.^(15)N isotopic labeling experiment confirms that nitrogen in produced ammonia originates from N_(2) in the electrolyte.The excellent NRR activity of surface hydrophobic MXenes is mainly due to surfactant molecules,which inhibit the entry of water molecules and the competitive HER,which have been verified by in situ FT-IR,DFT and molecular dynamics calculations.This strategy provides an ingenious method to design more active NRR electrocatalysts.展开更多
The role of the oxygen in AlGaN/GaN high electron mobility transistors(HEMTs)before and after semi-on state stress was discussed.Comparing with the electrical characteristics of the devices in vacuum,air,and oxygen at...The role of the oxygen in AlGaN/GaN high electron mobility transistors(HEMTs)before and after semi-on state stress was discussed.Comparing with the electrical characteristics of the devices in vacuum,air,and oxygen atmosphere,it is revealed that the oxygen has significant influence on the electric characteristics and the hot-carrier-stress-induced degradation of the device.Comparing with the situation in vacuum,the gate leakage increased an order of magnitude in oxygen and air atmosphere.Double gate structure was used to separate the barrier leakage and surface leakage of AlGaN/GaN HEMT it is found that surface leakage is the major influencing factor in gate leakage of SiN-passivated devices before and after semi-on state stress.During semi-on state stress in the oxygen atmosphere,the electric-field-driven oxidation process promoted the oxidation of the nitride layer,and the oxidation layer in the SiN/AlGaN interface leads to the decreasing of the surface leakage.展开更多
基金fundings from the National Natural Science Foundation of China (No. 51872173)Taishan Scholar Foundation of Shandong Province (No. tsqn201812068)+3 种基金Natural Science Foundation of Shandong Province (No. ZR2022JQ21)Higher School Youth Innovation Team of Shandong Province (No. 2019KJA013)Hong Kong Scholars Program (No. XJ2019042)Innovation and Technology Commission of the Hong Kong Special Administrative Region (No. ITC-CNERC14EG03)。
文摘Hydrophobic treatment of the catalyst surfaces can suppress the competitive hydrogen evolution reaction(HER) during the nitrogen reduction reaction(NRR).In this work,the surface of Ti_(3)C_(2)Ti_(x) MXene is modified by cetyltrimethylammonium bromide(CTAB) and trimethoxy(3,3,4,4,5,5,6,6,7,7,8,8,8-trideca fluorooctyl) silane(FOTS) to increase the hydrophobicity of MXenes.The ammonia(NH_(3)) production rate and faradaic efficiency(FE) are improved from 37.62 to 54.01 μg h^(-1)mg_(cat)^(-1).and 5.5% to 18.1% at-0.7 V vs.RHE,respectively after surface modification.^(15)N isotopic labeling experiment confirms that nitrogen in produced ammonia originates from N_(2) in the electrolyte.The excellent NRR activity of surface hydrophobic MXenes is mainly due to surfactant molecules,which inhibit the entry of water molecules and the competitive HER,which have been verified by in situ FT-IR,DFT and molecular dynamics calculations.This strategy provides an ingenious method to design more active NRR electrocatalysts.
基金supported by the National Natural Science Foundation of China(Grant No.62104167)the Natural Science Foundation of Jiangsu Province,China(Grant Nos.BK20210863 and BK20180966)by Qing Lan Project of Jiangsu Province,China.
文摘The role of the oxygen in AlGaN/GaN high electron mobility transistors(HEMTs)before and after semi-on state stress was discussed.Comparing with the electrical characteristics of the devices in vacuum,air,and oxygen atmosphere,it is revealed that the oxygen has significant influence on the electric characteristics and the hot-carrier-stress-induced degradation of the device.Comparing with the situation in vacuum,the gate leakage increased an order of magnitude in oxygen and air atmosphere.Double gate structure was used to separate the barrier leakage and surface leakage of AlGaN/GaN HEMT it is found that surface leakage is the major influencing factor in gate leakage of SiN-passivated devices before and after semi-on state stress.During semi-on state stress in the oxygen atmosphere,the electric-field-driven oxidation process promoted the oxidation of the nitride layer,and the oxidation layer in the SiN/AlGaN interface leads to the decreasing of the surface leakage.
