Chemical Sciences and Engineering Division, Argonne National Laboratory, 9700 South Cass Avenue, Lemont, IL 60439 (USA) http://www.iact.anl.gov.
Angew Chem Int Ed Engl. 2014 Nov 3;53(45):12132-6. doi: 10.1002/anie.201407236. Epub 2014 Sep 22.
The terraces, edges, and facets of nanoparticles are all active sites for heterogeneous catalysis. These different active sites may cause the formation of various products during the catalytic reaction. Here we report that the step sites of Pd nanoparticles (NPs) can be covered precisely by the atomic layer deposition (ALD) method, whereas the terrace sites remain as active component for the hydrogenation of furfural. Increasing the thickness of the ALD-generated overcoats restricts the adsorption of furfural onto the step sites of Pd NPs and increases the selectivity to furan. Furan selectivities and furfural conversions are linearly correlated for samples with or without an overcoating, though the slopes differ. The ALD technique can tune the selectivity of furfural hydrogenation over Pd NPs and has improved our understanding of the reaction mechanism. The above conclusions are further supported by density functional theory (DFT) calculations.
纳米粒子的晶面、边缘和台阶都是多相催化的活性位。这些不同的活性位在催化反应过程中可能导致不同产物的形成。在这里，我们报道了原子层沉积（ALD）方法可以精确地覆盖钯纳米粒子（NPs）的台阶位，而平台位仍然作为糠醛加氢的活性位。增加 ALD 生成的覆盖层厚度会限制糠醛在 Pd NPs 台阶位上的吸附，并提高呋喃的选择性。有无覆盖层的样品的呋喃选择性和糠醛转化率呈线性相关，尽管斜率不同。ALD 技术可以调节 Pd NPs 上糠醛加氢的选择性，并提高我们对反应机制的理解。上述结论还得到了密度泛函理论（DFT）计算的进一步支持。
