Zhang Long, Su Ya-Qiong, Chang Ming-Wen, Filot Ivo A W, Hensen Emiel J M
Laboratory of Inorganic Materials and Catalysis, Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB, Eindhoven, The Netherlands.
J Phys Chem C Nanomater Interfaces. 2019 Dec 26;123(51):31130-31141. doi: 10.1021/acs.jpcc.9b11079. Epub 2019 Dec 5.
Single-atom catalysts are at the center of attention of the heterogeneous catalysis community because they exhibit unique electronic structures distinct from nanoparticulate forms, resulting in very different catalytic performance combined with increased usage of often costly transition metals. Proper selection of a support that can stably keep the metal in a high dispersion is crucial. Here, we employ spin-polarized density functional theory and microkinetics simulations to identify optimum LaBO (B = Mn, Fe, Co, Ni) supported catalysts dispersing platinum group metals as atoms on their surface. We identify a strong correlation between the CO adsorption energy and the d-band center of the doped metal atom. These CO adsorption strength differences are explained in terms of the electronic structure. In general, Pd-doped surfaces exhibit substantially lower activation barriers for CO formation than the Rh- and Pt-doped surfaces. Strong Brønsted-Evans-Polanyi correlations are found for CO oxidation on these single-atom catalysts, providing a tool to predict promising compositions. Microkinetics simulations show that Pd-doped LaCoO is the most active catalyst for low-temperature CO oxidation. Moderate CO adsorption strength and low reaction barriers explain the high activity of this composition. Our approach provides guidelines for the design of highly active and cost-effective perovskite supported single-atom catalysts.
单原子催化剂是多相催化领域关注的焦点，因为它们具有不同于纳米颗粒形式的独特电子结构，这导致其催化性能有很大差异，同时还能提高通常成本较高的过渡金属的利用率。正确选择能够稳定保持金属高分散性的载体至关重要。在此，我们采用自旋极化密度泛函理论和微观动力学模拟来确定最佳的LaBO（B = Mn、Fe、Co、Ni）负载型催化剂，这些催化剂可将铂族金属以原子形式分散在其表面。我们发现CO吸附能与掺杂金属原子的d带中心之间存在很强的相关性。这些CO吸附强度差异可以从电子结构方面进行解释。一般来说，与Rh和Pt掺杂的表面相比，Pd掺杂的表面对CO形成的活化能垒要低得多。在这些单原子催化剂上发现了CO氧化的强布朗斯特-埃文斯-波兰尼相关性，这为预测有前景的组成提供了一种工具。微观动力学模拟表明，Pd掺杂的LaCoO是低温CO氧化最活跃的催化剂。适度的CO吸附强度和较低的反应能垒解释了该组成的高活性。我们的方法为设计高活性和高性价比的钙钛矿负载单原子催化剂提供了指导。
