The anchoring effect between surface hydroxyls (–OH) and metal species has been extensively utilized to enhance catalyst stability. Nevertheless, few studies have investigated the impact of alloying process involving different types of –OH species. In this research, we discovered that the formation of the alloy particles Pt 3 Co was significantly influenced by the presence of distinct –OH species on Al 2 O 3 . Intriguingly, those Pt 3 Co alloy particles exclusively formed on α-Al 2 O 3 owing to the weak interaction between both Pt and Co species and the triply bridging hydroxyls (µ 3 -OH). In contrast, Pt and Co species were found to be separately dispersed on γ-Al 2 O 3 because of the strong anchoring effect of terminal hydroxyls (µ 1 -OH), especially for Co atoms. Density functional theory (DFT) calculations highlighted the difference in adsorption energies of the two metals on different hydroxyl groups, providing a theoretical rationale for the influence of hydroxyl groups on alloy formation. The presence of Pt 3 Co alloy resulted in a fourfold increase in the specific catalytic rate of Pt 3 Co/α-Al 2 O 3 in CO-PROX compared to Pt 3 Co/γ-Al 2 O 3 . Arguably for the first time, this study demonstrates the association between alloy formation and –OH groups, providing a unique perspective on the design of alloy catalysts.
Yuhui Cui,Jinghao Lu,Lijuan Yang,Zheng Hao,Runjin Wu,Qian Li,Shijia Xu,Libin Yang
In proton exchange membrane fuel cells (PEMFCs), the most advanced catalysts are mainly carbon loaded with platinum (Pt), but the cathodic catalytic active center is too low to match the oxidation activity and rate at the anode. Co atoms doped into the lattice of Pt alloy change the electronic structure of platinum and reduce the binding energy of oxygen atoms. Au or Rh atoms embedded into the lattice of Pt 3 Co alloy compensate the defect and enhance the activity and rate of the oxygen reduction. Through base on density functional theory (DFT), the adsorption energy for oxygen on Pt 3 Co, Au-Pt 3 Co, and Rh-Pt 3 Co and the segregation energy of Co atoms were calculated. The results show that Au or Rh doped weakens the binding energy of Pt for oxygen on the Pt 3 Co alloy and improves the activity and stability of oxygen reduction. Compared with Rh, the introduction of Au element shows better effects in the electrocatalytic reaction process. Graphical Abstract
危险品化学品经营许可证（带存储）