资源类型

期刊论文 4

年份

2023 3

关键词

检索范围：

排序： 展示方式：

Insights into carbon-based materials for catalytic dehydrogenation of low-carbon alkanes and ethylbenzene

《化学科学与工程前沿（英文）》 2023年 第17卷 第11期   页码 1623-1648 doi: 10.1007/s11705-023-2328-6

摘要： Direct dehydrogenation with high selectivity and oxidative dehydrogenation with low thermal limit has been regarded as promising methods to solve the increasing demands of light olefins and styrene. Metal-based catalysts have shown remarkable performance for these reactions, such as Pt, CrOx, Co, ZrOx, Zn and V. Compared with metal-based catalysts, carbon materials with stable structure, rich pore texture and large surface area, are ideal platforms as the catalysts and the supports for dehydrogenation reactions. In this review, carbon materials applied in direct dehydrogenation and oxidative dehydrogenation reactions including ordered mesoporous carbon, carbon nanodiamond, carbon nanotubes, graphene and activated carbon, are summarized. A general introduction to the dehydrogenation mechanism and active sites of carbon catalysts is briefly presented to provide a deep understanding of the carbon-based materials used in dehydrogenation reactions. The unique structure of each carbon material is presented, and the diversified synthesis methods of carbon catalysts are clarified. The approaches for promoting the catalytic activity of carbon catalysts are elaborated with respect to preparation method optimization, suitable structure design and heteroatom doping. The regeneration mechanism of carbon-based catalysts is discussed for providing guidance on catalytic performance enhancement. In addition, carbon materials as the support of metal-based catalysts contribute to exploiting the excellent catalytic performance of catalysts due to superior structural characteristics. In the end, the challenges in current research and strategies for future improvements are proposed.

关键词： carbon materials     dehydrogenation     active sites     mechanism     catalytic performance     support    

HTML PDF 收藏

Formic acid dehydrogenation reaction on high-performance PdAu alloy nanoparticles prepared by the eco-friendly

《能源前沿（英文）》   页码 751-762 doi: 10.1007/s11708-023-0895-3

摘要： Dehydrogenation of formic acid (FA) is considered to be an effective solution for efficient storage and transport of hydrogen. For decades, highly effective catalysts for this purpose have been widely investigated, but numerous challenges remain. Herein, the PdxAu1−x (x = 0, 0.2, 0.4, 0.5, 0.6, 0.8, 1) alloys over the whole composition range were successfully prepared and used to catalyze FA hydrogen production efficiently near room temperature. Small PdAu nanoparticles (5–10 nm) were well-dispersed and supported on the activated carbon to form PdAu solid solution alloys via the eco-friendly slow synthesis methodology. The physicochemical properties of the PdAu alloys were comprehensively studied by utilizing various measurement methods, such as X-ray diffraction (XRD), N2 adsorption–desorption, high angle annular dark field-scanning transmission electron microscope (HAADF-STEM), X-ray photoelectrons spectroscopy (XPS). Notably, owing to the strong metal-support interaction (SMSI) and electron transfer between active metal Au and Pd, the Pd0.5Au0.5 obtained exhibits a turnover frequency (TOF) value of up to 1648 h−1 (313 K, nPd+Au/nFA = 0.01, nHCOOH/nHCOONa = 1:3) with a high activity, selectivity, and reusability in the FA dehydrogenation.

关键词： FA dehydrogenation     face-centred cubic structures     PdAu solid solution alloy nanoparticles     slow synthesis methodology     SMSI effect    

HTML PDF 收藏

Effects of ancillary ligands in acceptorless benzyl alcohol dehydrogenation mediated by phosphine-free

《化学科学与工程前沿（英文）》 2023年 第17卷 第3期   页码 314-325 doi: 10.1007/s11705-022-2219-2

摘要： Acceptorless alcohol dehydrogenation stands out as one of the most promising strategies in hydrogen storage technologies. Among various catalytic systems for this reaction, cost-effective molecular catalysts using phosphine-free ligands have gained considerable attention. However, the central challenge for using non-precious metals is to overcome the propensity of reacting by one-electron pathway. Herein, we synthesized a phosphine-free η5-C5Me5-Co complex by using the metal–ligand cooperative strategy and compared its activity with analogous catalysts toward acceptorless alcohol dehydrogenation. The catalyst showed excellent performance with a turnover number of 130.4 and a selectivity close to 100%. The improved performance among the class of η5-C5Me5-Co complexes could be attributed to the more accessible Co center and its cooperation with the redox-active ligand. To further study the systematic structure-activity relationship, we investigated the electronic structures of η5-C5Me5-Co complexes by a set of characterizations. The results showed that the redox-active ligand has a significant influence on the η5-C5Me5-Co moiety. In the meantime, the proximal O−/OH group is beneficial for shuttling protons. For the catalytic cycle, two dehydrogenation scenarios were interrogated through density functional theory, and the result suggested that the outer-sphere pathway was preferred. The formation of a dihydrogen complex was the rate-determining step with a ΔG value of 16.9 kcal∙mol‒1. The electron population demonstrated that the η5-C5Me5 ligand played a key role in stabilizing transition states during dehydrogenation steps. This work identified the roles of vital ligand components to boost catalytic performance and offered rationales for designing metal–ligand cooperative nonprecious metal complexes.

关键词： acceptorless alcohol dehydrogenation     η5-C5Me5-Co     metal–ligand cooperation     theoretical calculation    

HTML PDF 收藏

stabilization effect of Al2O3 on unconventional Pb/SiO2 catalyst for propane dehydrogenation

《化学科学与工程前沿（英文）》 2023年 第17卷 第10期   页码 1423-1429 doi: 10.1007/s11705-023-2315-y

摘要： Similar to Sn, Pb located at the same group (IVA) in the periodic table of elements, can also catalyze propane dehydrogenation to propene, while a fast deactivation can be observed. To enhance the stability, the traditional carrier Al2O3 with a small amount, was introduced into Pb/SiO2 catalyst in this study. It has been proved that Al2O3 can inhibit the reduction of PbO, and weaken the agglomeration and loss of Pb species due to its enhanced interaction with Pb species. As a result, 3Al15Pb/SiO2 catalyst exhibits a much higher stability up to more than 150 h. In addition, a simple schematic diagram of the change of surface species on the catalyst surface after Al2O3 addition was also proposed.

关键词： Pb/SiO2     Al2O3     propane dehydrogenation     propene     stability    

HTML PDF 收藏

标题 作者 时间 类型 操作

Insights into carbon-based materials for catalytic dehydrogenation of low-carbon alkanes and ethylbenzene

期刊论文

Formic acid dehydrogenation reaction on high-performance PdAu alloy nanoparticles prepared by the eco-friendly

期刊论文

Effects of ancillary ligands in acceptorless benzyl alcohol dehydrogenation mediated by phosphine-free

期刊论文

stabilization effect of Al2O3 on unconventional Pb/SiO2 catalyst for propane dehydrogenation

期刊论文