为了优选TiO_(2)电极最适宜尺寸,提高栽培基质pH值在线检测的综合性能,利用磁控溅射法将TiO_(2)薄膜沉积在氧化铟锡/玻璃(Indium Tin Oxide/Glass,ITO/Glass)基板上,制备不同膜厚和面积的pH敏感电极,搭配固态Ag/AgCl参比电极构建pH传感...为了优选TiO_(2)电极最适宜尺寸,提高栽培基质pH值在线检测的综合性能,利用磁控溅射法将TiO_(2)薄膜沉积在氧化铟锡/玻璃(Indium Tin Oxide/Glass,ITO/Glass)基板上,制备不同膜厚和面积的pH敏感电极,搭配固态Ag/AgCl参比电极构建pH传感器.利用扫描电子显微镜(SEM)观察电极薄膜表面形貌发展规律,分析响应特性;在标准pH缓冲溶液中测试传感器响应特性.结果表明:较厚的TiO_(2)敏感膜具有更好的疏松多孔结构,传感器响应稳定性优异,但是响应灵敏度差;综合优选膜厚度为200 nm、膜尺寸为15 mm×15 mm的TiO_(2)敏感电极,pH值响应综合性能接近玻璃电极传感器;利用优选传感器在栽培基质pH检测应用试验中,pH检测最大绝对误差为0.52单位;通过对误差规律的总结,构建质量含水率补偿模型;经过质量含水率补偿后,pH检测最大绝对误差降低到了0.12单位,相对误差在5%以下,满足栽培基质pH值在线检测性能要求.展开更多
Unveiling the active site of an electrocatalyst is fundamental for the development of efficient electrode material.For the two-electron water oxidation to produce H_(2)O_(2),competitive reactions,including four-and on...Unveiling the active site of an electrocatalyst is fundamental for the development of efficient electrode material.For the two-electron water oxidation to produce H_(2)O_(2),competitive reactions,including four-and one-electron water oxidation and surface reconstruction derived from the high-oxidative environment co-existed,leading to great challenges to identify the real active sites on the electrode.In this work,Ti/TiO_(2)-based electrodes calcined under air,nitrogen,or urea atmospheres were selected as electrocatalysts for two-electron water oxidation.Electrochemical analyses were applied to evaluate the catalytic activity and selectivity.The morphological and current change on the electrode surface were determined by scanning electrochemical microscopy,while the chemical and valence evolutions with depth distributions were tested by XPS combined with cluster argon ion sputtering.The results demonstrated that Ti/TiO_(2) nanotube arrays served as the support,while the functional groups of carbonyl groups and pyrrolic nitrogen derived from the co-pyrolysis with urea were the active sites for the H_(2)O_(2) production.This finding provided a new horizon to design efficient catalysts for H_(2)O_(2) production.展开更多
基金Project(2021JJ30792) supported by the Natural Science Foundation of Hunan Province,ChinaProject(52170031) supported by the National Natural Science Foundation of ChinaProject supported by the Fundamental Research Funds for the Central Universities,China。
文摘Unveiling the active site of an electrocatalyst is fundamental for the development of efficient electrode material.For the two-electron water oxidation to produce H_(2)O_(2),competitive reactions,including four-and one-electron water oxidation and surface reconstruction derived from the high-oxidative environment co-existed,leading to great challenges to identify the real active sites on the electrode.In this work,Ti/TiO_(2)-based electrodes calcined under air,nitrogen,or urea atmospheres were selected as electrocatalysts for two-electron water oxidation.Electrochemical analyses were applied to evaluate the catalytic activity and selectivity.The morphological and current change on the electrode surface were determined by scanning electrochemical microscopy,while the chemical and valence evolutions with depth distributions were tested by XPS combined with cluster argon ion sputtering.The results demonstrated that Ti/TiO_(2) nanotube arrays served as the support,while the functional groups of carbonyl groups and pyrrolic nitrogen derived from the co-pyrolysis with urea were the active sites for the H_(2)O_(2) production.This finding provided a new horizon to design efficient catalysts for H_(2)O_(2) production.
