Chasvin Nilda, Švenda Petr, Pronsato Estela, Diez Alejandra, Volpe María Alicia, Johánek Viktor, Pistonesi Carolina
Departamento de Química, Universidad Nacional del Sur, & INQUISUR, UNS-CONICET, Av. Alem 1253, 8000 Bahía Blanca, Argentina.
Departamento de Física, Universidad Nacional del Sur & IFISUR (UNS-CONICET), Av. Alem 1253, 8000 Bahía Blanca, Argentina.
Phys Chem Chem Phys. 2021 Oct 27;23(41):23567-23575. doi: 10.1039/d1cp03472c.
The adsorption and dissociation of ethanol on Pt/β-MoC with a low noble metal loading (0.1 wt%) is studied in the context of catalytic H production from alcohols. X-ray diffraction and experimental results indicate that Pt modifies the lattice parameters of β-MoC. In line with this, density functional theory calculations indicate that the Mo-Mo distances are increased due to the presence of Pt. An experimental X-ray photoelectron spectroscopy study indicates that the chemical state of both molybdenum and carbon in Pt/β-MoC are very different from those in the Pt-free carbide, which is also in agreement with the DFT results, which indicate that the Pt atoms generate a redistribution of charge density in their environment. Temperature programmed reaction analysis shows that at temperatures higher than 530 K, a two-fold increase in the production of H, CH and CH is observed for Pt/β-MoC as compared to β-MoC, suggesting a higher catalytic activity for the Pt-containing carbide than for the pristine catalyst. Additionally, H production from ethanol on Pt/β-MoC presents a higher activation energy (0.64 eV) than that corresponding to pristine molybdenum carbide. In agreement with this experimental result, climbing image-nudged elastic band (CI-NEB) calculations indicate that the energy barrier linked to the formation of H from ethanol increases with the presence of platinum. It is concluded that the low Pt loading notably modifies the catalytic pattern of molybdenum carbide, rendering it a highly active catalyst for ethanol decomposition.
在醇类催化制氢的背景下,研究了低贵金属负载量(0.1 wt%)的Pt/β-MoC上乙醇的吸附和解离。X射线衍射和实验结果表明,Pt改变了β-MoC的晶格参数。与此一致,密度泛函理论计算表明,由于Pt的存在,Mo-Mo间距增大。一项实验X射线光电子能谱研究表明,Pt/β-MoC中钼和碳的化学状态与无Pt碳化物中的化学状态有很大不同,这也与DFT结果一致,DFT结果表明Pt原子在其周围环境中产生了电荷密度的重新分布。程序升温反应分析表明,在高于530 K的温度下,与β-MoC相比,Pt/β-MoC的H、CH和CH产量增加了两倍,这表明含Pt碳化物的催化活性高于原始催化剂。此外,Pt/β-MoC上乙醇制氢的活化能(0.64 eV)高于原始碳化钼。与该实验结果一致,爬坡图像推挤弹性带(CI-NEB)计算表明,乙醇生成H的能垒随着铂的存在而增加。得出的结论是,低Pt负载量显著改变了碳化钼的催化模式,使其成为乙醇分解的高活性催化剂。
Phys Chem Chem Phys. 2021-10-27
J Phys Chem B. 2003-7-24
Materials (Basel). 2022-5-25