催化基底表面亲水改性对氢气催化氧化效率影响的密度泛函研究

DFT study on effect of hydrophilic modification of catalyst on oxidation efficiency of hydrogen gas

催化剂表面亲疏水性改性是一种常见的调控手段,其对催化剂催化活性、选择性和稳定性有着重要的影响。以氢气催化氧化转化为水为研究对象,从分子水平出发,通过多尺度密度泛函理论(DFT)计算了催化剂在不同程度的表面亲水改性后对水和氢气的吸附作用,并研究了吸附对于反应效率的影响。结果表明,随着表面亲水性的增强,催化剂表面对水吸附越来越多,而受体积排斥效应影响,氢气的吸附量越来越少。而对于同一催化剂表面,增大水分子的均相密度量可促进氢气在表面的吸附。该理论结果不仅很好地解释了催化剂表面亲水性对于催化活性的影响,且为表界面反应的效率调控与强化提供了思路。

Hydrophilic surface modification of the catalyst surface is a common regulation method,which has an important influence on the catalytic activity,selectivity and stability of the catalyst.In this study,the hydrogenoxygen catalytic system was used as the research object,and the adsorption of hydrogen and water on different hydrophilic surfaces was calculated by multiscale density function theory(DFT)under molecular level.Finally,the effect of adsorption on reactive rate was studied.The results showed that the adsorption amount of water increased with more hydrophilic surface while the adsorption amount of hydrogen decreased.In addition,increasing bulk water density enhanced the adsorption of hydrogen on the surface.The above results not only explained the influence of hydrophilicity on the catalytic activity of the catalyst,but also had helpful guiding for the adjustment and enhancement of the surface reaction process.