Yunjie Ding

Bio: Yunjie Ding is an academic researcher from Dalian Institute of Chemical Physics. The author has contributed to research in topics: Catalysis & Hydroformylation. The author has an hindex of 30, co-authored 152 publications receiving 3675 citations. Previous affiliations of Yunjie Ding include Chinese Academy of Sciences.

Enhanced ethanol production inside carbon-nanotube reactors containing catalytic particles

Abstract: Carbon nanotubes (CNTs) have well-defined hollow interiors and exhibit unusual mechanical and thermal stability as well as electron conductivity1. This opens intriguing possibilities to introduce other matter into the cavities2,3,4,5, which may lead to nanocomposite materials with interesting properties or behaviour different from the bulk6,7,8. Here, we report a striking enhancement of the catalytic activity of Rh particles confined inside nanotubes for the conversion of CO and H2 to ethanol. The overall formation rate of ethanol (30.0 mol mol−1Rh h−1) inside the nanotubes exceeds that on the outside of the nanotubes by more than an order of magnitude, although the latter is much more accessible. Such an effect with synergetic confinement has not been observed before in catalysis involving CNTs. We believe that our discovery may be of a quite general nature and could apply to many other processes. It is anticipated that this will motivate theoretical and experimental studies to further the fundamental understanding of the host–guest interaction within carbon and other nanotube systems.

High Alcohols Synthesis via Fischer–Tropsch Reaction at Cobalt Metal/Carbide Interface

Abstract: Utilization of nonprecious transition metals for high alcohols synthesis is of a great importance in heterogeneous catalysis. We synthesized successfully cobalt metal-carbide (Co–Co2C) catalysts, which present remarkable activity and selectivity for high alpha-alcohols via the Fischer–Tropsch reaction. The formation of the stable cobalt carbide and the Co–Co2C interface are found to be essential for the observed reactivity. Density functional theory calculations show that Co2C is highly efficient for CO nondissociative adsorption, behaving as noble-metal-like, whereas the Co metal is highly active for CO dissociative adsorption and the subsequent carbon-chain growth. The interface between the cobalt metal and its carbide phase, as well as the dual sites available at the interface for facile CO insertion to hydrocarbon, could be used to rationalize the design of the nonprecious transition metal catalysts for the oxygenates in syngas conversion.

Selective hydrogenolysis of glycerol to 1,3-propanediol over a Pt/WO3/TiO2/SiO2 catalyst in aqueous media

Abstract: SiO2-supported Pt/WO3/TiO2 catalysts were prepared; they were found to be more active and selective than the Pt/WO3/TiO2 catalyst for glycerol hydrogenolysis to 1,3-propanediol in a slurry batch reactor. The influences of catalyst component, reaction medium, reaction temperature, H2 pressure and reaction time on glycerol hydrogenolysis over the Pt/WO3/TiO2/SiO2 catalyst were investigated. XRD, TEM, NH3-TPD and Py-IR characterization were employed to reveal the roles of WO3 and TiO2 in the performance of the Pt based-catalysts. XRD patterns and TEM images showed that the presence of TiO2 species in the catalyst favored the dispersion of platinum. The weak Bronsted acid sites formed by addition of WO3 to the catalyst were concluded to play a key role in selective formation of 1,3-propanediol, based on the results of NH3-TPD and Py-IR characterization.

Insight into the Formation of Co@Co2C Catalysts for Direct Synthesis of Higher Alcohols and Olefins from Syngas

Abstract: Cobalt carbide (Co2C) has recently been reported to be efficient for the conversion of syngas (CO+H2) to lower olefins (C2–C4) and higher alcohols (C2+ alcohols); however, its properties and formation conditions remain ambiguous. On the basis of our previous investigations concerning the formation of Co2C, the work herein was aimed at defining the mechanism by which the manganese promoter functions in the Co-based catalysts supported on activated carbon (CoxMn/AC). Experimental studies validated that Mn facilitates the dissociation and disproportionation of CO on the surface of catalyst and prohibits H2 adsorption to some extent, creating a relative C-rich and H-lean surface chemical environment. We advocate that the surface conditions result in the transformation from metallic Co to Co2C phase under realistic reaction conditions to form Co@Co2C nanoparticles, in which residual small Co0 ensembles (<6 nm) distribute on the surface of Co2C nanoparticles (∼20 nm). Compared with the Co/AC catalyst, where the...

Effect of La2O3 doping on syntheses of C1–C18 mixed linear α-alcohols from syngas over the Co/AC catalysts

Abstract: Activated carbon-supported La-promoted Co catalysts with different La dopings (15Co– x La/AC) were prepared by the co-impregnation method and investigated by means of CO hydrogenation, XRD, TPR-MS, CO adsorption and TPSR-MS techniques. The results showed that mixed linear α-alcohols (C 1 –C 18 ) can be directly synthesized from syngas over the La-doped 15Co/AC catalysts under mild conditions and that the selectivity towards alcohols was improved by doping La into the 15Co/AC catalysts. It was found that the reducibility of the 15Co– x La/AC catalyst decreased and the Co dispersion improved due to the strong interaction between Co and La 2 O 3 species. La 2 O 3 can promote the formation of cobalt carbides (Co 2 C), which are postulated to play an important role in the syntheses of the mixed linear α-alcohols. On the other hand, high Co dispersion and an appropriate ratio of Co 2+ /Co 0 can enhance the activity of CO hydrogenation.

Metal Catalysts for Heterogeneous Catalysis: From Single Atoms to Nanoclusters and Nanoparticles.

Abstract: Metal species with different size (single atoms, nanoclusters, and nanoparticles) show different catalytic behavior for various heterogeneous catalytic reactions. It has been shown in the literature that many factors including the particle size, shape, chemical composition, metal–support interaction, and metal–reactant/solvent interaction can have significant influences on the catalytic properties of metal catalysts. The recent developments of well-controlled synthesis methodologies and advanced characterization tools allow one to correlate the relationships at the molecular level. In this Review, the electronic and geometric structures of single atoms, nanoclusters, and nanoparticles will be discussed. Furthermore, we will summarize the catalytic applications of single atoms, nanoclusters, and nanoparticles for different types of reactions, including CO oxidation, selective oxidation, selective hydrogenation, organic reactions, electrocatalytic, and photocatalytic reactions. We will compare the results o...

Heterogeneous single-atom catalysis

Abstract: Single-atom catalysis has arguably become the most active new frontier in heterogeneous catalysis. Aided by recent advances in practical synthetic methodologies, characterization techniques and computational modelling, we now have a large number of single-atom catalysts (SACs) that exhibit distinctive performances for a wide variety of chemical reactions. This Perspective summarizes recent experimental and computational efforts aimed at understanding the bonding in SACs and how this relates to catalytic performance. The examples described here illustrate the utility of SACs in a broad scope of industrially important reactions and highlight the advantages these catalysts have over those presently used. SACs have well-defined active centres, such that unique opportunities exist for the rational design of new catalysts with high activities, selectivities and stabilities. Indeed, given a certain practical application, we can often design a suitable SAC; thus, the field has developed very rapidly and afforded promising catalyst leads. Moreover, the control we have over certain SAC structures paves the way for designing base metal catalysts with the activities of noble metal catalysts. It appears that we are entering a new era of heterogeneous catalysis in which we have control over well-dispersed single-atom active sites whose properties we can readily tune. Single-atom catalysts are heterogeneous materials featuring active metals sites atomically dispersed on a surface. This Review describes methods by which we prepare and characterize these materials, as well as how we can tune their catalytic performance in a variety of important reactions.