Thermal stability and protective properties of phenylphosphonic acid on Cu(111)
Thermal stability and protective properties of phenylphosphonic acid on Cu(111)
复制标题
苯基膦酸对Cu(111)的热稳定性及保护性能
DOI：
10.1016/j.apsusc.2022.154036
复制
发表时间：
2022
影响因子：
6.7
通讯作者：
Xu, Ye
中科院分区：
文献类型：
--
作者：
Kalinovych, Viacheslav;Saeedur Rahman, Md.;Piliai, Lesia;Kosto, Yuliia;Mehl, Sascha L.;Skála, Tomáš;Matolínová, Iva;Matolín, Vladimír;Prince, Kevin C.;Xu, Ye
采用同步辐射技术结合密度泛函理论研究了苯基膦酸（PPA）在Cu（111）表面的吸附行为。脱氢的苯基膦酸分子（PP）通过氧原子以三齿几何结构与Cu（111）强烈结合，显示出在150-300 °C的温度范围内是主要的表面物种。稳定的PP吸附层基本上保护Cu（111）表面在暴露于环境条件期间免于氧化。PPA吸附层在375 °C下的热处理通过几个通道引发分子分解：P-O键断裂形成C6 H5 PO 2; C-P键断裂形成苯基和PO 3;以及C-H键断裂形成C6 H4 PO 3。所有三个反应步骤具有1.7- 1.8eV的活化势垒。小的产物如O、H和苯基可以立即进一步反应并解吸，而剩余的膦酸酯物质进行缩合。在较高温度下退火后，膦酸酯基团进一步从富氧物质还原为富磷物质，其在500 °C处理后形成大部分剩余的吸附物。
Phenylphosphonic acid (PPA) adsorbed on Cu(111) has been studied by synchrotron radiation-based techniques in combination with density functional theory calculations. The dehydrogenated phenylphosphonic acid molecule (PP) strongly bound in a tridentate geometry through oxygen atoms to Cu(111) is shown to be the dominant surface species in the temperature range 150–300 °C. The stable PP adlayer substantially protects the Cu(111) surface from oxidation during exposure to ambient conditions. Thermal treatment of the PPA adlayer at 375 °C initiates molecular decomposition through several channels: P–O bond scission forming C6H5PO2; C–P bond scission forming phenyl and PO3; and C–H bond scission forming C6H4PO3. All three reaction steps have activation barriers of 1.7–1.8 eV. Small products such as O, H, and phenyl can immediately react further and desorb, while the remaining phosphonate species undergo condensation. After annealing at a higher temperature, the phosphonate group is further reduced from oxygen-rich to phosphorus-rich species, which form the majority of remaining adsorbates after 500 °C treatment.