Elucidating the Influence of Metal Surface Composition on Organic Adsorbate Binding Using Active Particle Dynamics
Elucidating the Influence of Metal Surface Composition on Organic Adsorbate Binding Using Active Particle Dynamics
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DOI：
10.1021/acs.jpcc.2c05907
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发表时间：
2023-01-09
影响因子：
3.7
通讯作者：
Schwartz, Daniel K.
中科院分区：
文献类型：
--
作者：
Greydanus, Benjamin;Medlin, J. Will;Schwartz, Daniel K.
有机化合物在金属表面的吸附强度对金属组成非常敏感，它们在许多催化反应中起着核心作用，有助于控制反应物的覆盖范围，改变整体反应速度。虽然吸附能在真空和气相环境中很容易测量和计算，但在液相反应中，溶剂的存在会极大地改变吸附能。然而，金属成分对液体环境中结合强度的影响还不是很清楚，主要是因为很难准确地原位测量液体中金属表面的有机结合。在这里，我们利用活性粒子在水中的运动来探测一种有机吸附物(呋喃甲醛)在一系列金属表面(纯Pd、纯铂和四种PdAu合金成分)上的吸附能，以阐明金属成分的影响。具有特定金属组成催化帽的Janus颗粒都表现出由于消耗H_2O_2而产生的活性运动；吸附结合是通过活性运动速度的降低来推断的，并由Langmuir吸附等温线来模拟。用测得的吸附亲和能求出了呋喃甲醛在不同金属上的吸附热。结果表明，Pd表面对呋喃甲醛的结合强度比Pt表面强约10kJ/mol。此外，还发现随着Pd含量的增加，呋喃甲醛在合金上的吸附量单调增加。本文报道的数据有助于准确理解在有溶剂存在的情况下的有机吸附，以及金属表面在调节吸附强度以优化液体中的催化过程中的作用。
The adsorption strengths of organic compounds on metal surfaces are sensitive to the metal composition, and they play a central role in many catalytic reactions, helping to control the coverage of the reactant and altering the overall reaction rate. While adsorption energies are straightforward to measure and calculate in vacuum and gas-phase environments, adsorption energetics can be dramatically altered by the presence of solvent in liquid-phase reactions. However, the effects of metal composition on binding strengths in a liquid environment are less well understood, primarily due to the difficulty of accurate in situ measurements of organic binding on metal surfaces in the liquid phase. Here, we utilize the motion of active particles in water to probe the adsorption energies of an organic adsorbate (furfural) on a range of metal surfaces (pure Pd, pure Pt, and four PdAu alloy compositions) to elucidate the effect of metal composition. Janus particles with catalytic caps of particular metal compositions all exhibited active motion resulting from consumption of H2O2; adsorbate binding was inferred through the decrease in the velocity of active motion and was modeled by a Langmuir adsorption isotherm. The measured adsorption affinities were used to extract the adsorption enthalpy of furfural on the different metals. The Pd surface was found to bind furfural more strongly than the Pt surface by some 10 kJ/mol. Furthermore, the adsorption of furfural on the alloys was found to increase monotonically in magnitude with Pd content. The data reported herein aid the development of accurate understanding of organic adsorption in the presence of solvent and the role of the metal surface in tuning adsorption strengths to optimize catalytic processes in the liquid phase.