当前位置: X-MOL 学术Tribol. Lett. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Inducing High-Energy-Barrier Tribochemical Reaction Pathways; Acetic Acid Decomposition on Copper
Tribology Letters ( IF 3.2 ) Pub Date : 2021-02-17 , DOI: 10.1007/s11249-021-01407-z
Resham Rana , Robert Bavisotto , Nicholas Hopper , Wilfred T. Tysoe

The surface tribological chemistry of acetic acid on copper is studied using an ultrahigh vacuum tribometer, supplemented by first-principles density functional theory calculations of the surface structure and reaction pathways. Acetic acid forms η2-acetate species on bridge sites at room temperature as identified by reflection–absorption infrared spectroscopy. Rubbing the surface with a tungsten carbide ball reduces the amount of carbon and oxygen in the rubbed region at the same rates to leave some carbon and oxygen on the surface. This is different from the thermal decomposition pathway, where heating to ~ 580 K removes all oxygen, but leave a small amount of carbon on the surface. It is postulated that this arises because sliding along a direction aligned within the plane of the adsorbed acetate species can induce a high-energy-barrier pathway in which the η2-acetate tilts to form an η1-acetate that can react to form a bent CO2δ− species that decomposes to evolve carbon monoxide and deposit atomic oxygen on the surface. Repeated acetic acid dosing and rubbing reduces the total amount of acetic acid that can adsorb on the surface by ~ 50% after ~ 4 cycles, resulting is a stable, low-friction film. At this point, the adsorbed acetic acid is completely tribochemically removed. This suggests that adsorbed acetic acid can form a self-healing film in which any wear of the low-friction film will then allow it to be replenished by shear-induced decomposition of adsorbed acetate species.



中文翻译:

诱导高能垒摩擦化学反应途径;铜上的乙酸分解

使用超高真空摩擦计研究了乙酸在铜上的表面摩擦学化学,并辅以有关表面结构和反应途径的第一原理密度泛函理论计算。乙酸形式η 2反射吸收红外光谱法确定室温下桥位上的乙酸盐种类。用碳化钨球摩擦表面会以相同的速率减少摩擦区域中的碳和氧,从而在表面上留下一些碳和氧。这与热分解途径不同,在热分解过程中,加热至580 K可以除去所有氧气,但表面会残留少量碳。据推测,这是因为产生沿着吸附醋酸物种的平面内对齐的方向滑动可诱导高能量势垒途径,其中的η 2 -乙酸甲酯倾斜以形成η 1 -乙酸盐,可以反应以形成弯曲的CO 2 δ−会分解生成一氧化碳并在表面沉积原子氧的物种。大约4个循环后,反复进行乙酸定量和摩擦处理,可以使表面吸附的乙酸总量减少约50%,从而形成稳定的低摩擦膜。此时,通过摩擦化学方法将吸附的乙酸完全去除。这表明吸附的乙酸可以形成自修复膜,在该膜中,低摩擦膜的任何磨损都将通过剪切诱导的吸附的乙酸物质的分解来补充。

更新日期:2021-02-17
down
wechat
bug