Cui Meiyang, Johnson Grayson, Zhang Zhiyong, Li Shuang, Hwang Sooyeon, Zhang Xu, Zhang Sen
Department of Chemistry, University of Virginia, Charlottesville, VA 22904, USA.
Nanoscale. 2020 Jul 14;12(26):14068-14075. doi: 10.1039/d0nr03203d. Epub 2020 Jun 25.
Monodisperse AgPd nanoparticles (NPs) were synthesized and studied as an efficient catalyst for electrocatalytic CO reduction by modulating bimetallic compositions. The mechanistic studies, based on density functional theory (DFT) calculations and environmental diffuse reflectance infrared Fourier-transform spectroscopy (DRIFTS) analysis, revealed that the incorporation of Ag in AgPd NPs can effectively weaken CO adsorption on all possible Pd surface sites (the ligand effects), and more importantly, disrupt the strongest multi-centered CO-binding sites (the ensemble effects). With properly tuned CO adsorption, which is ordinarily too strong over pure Pd, AgPd NPs were found to be the best composition for the efficient production of CO. They deliver a unity conversion of CO to CO with a high mass activity of 15.2 mA mg at -0.8 V vs. the reversible hydrogen electrode (RHE) and high stability with minimal change in the CO faradaic efficiency (FE) after 12 hours of operation.
通过调节双金属组成，合成了单分散的AgPd纳米颗粒（NPs），并将其作为电催化CO还原的高效催化剂进行了研究。基于密度泛函理论（DFT）计算和环境漫反射红外傅里叶变换光谱（DRIFTS）分析的机理研究表明，在AgPd NPs中引入Ag可以有效减弱CO在所有可能的Pd表面位点上的吸附（配体效应），更重要的是，破坏最强的多中心CO结合位点（集合效应）。通过适当调节通常在纯Pd上吸附过强的CO吸附，发现AgPd NPs是高效生产CO的最佳组成。在相对于可逆氢电极（RHE）为-0.8 V时，它们实现了CO到CO的单位转化率，具有15.2 mA mg的高质量活性，并且在运行12小时后具有高稳定性，CO法拉第效率（FE）变化最小。
