We demonstrate the formation of intermixed phases and self assembled molecular templates on the Au(111) surface. The templates are stabilized by hydrogen bonding between melamine molecules with trigonal symmetry and linear PTCDI (perylene tetra-carboxylic di-imide) molecules. When annealed, these molecules spontaneously form either a chiral intermixed phase or a honeycomb arrangement in which vertexes and edges correspond respectively to melamine and PTCDI molecules. We also observe minority phases with more complex intermolecular junctions. The use of these networks as templates is demonstrated by the controlled capture of fullerenes within the pores of the network to form dimers, hexamers, and heptamers. Our results confirm that bimolecular templates can be realized on a range of substrates.

We have investigated the ordered phases of the perylene derivatives perylene-3,4,9,10-tetracarboxylic-3,4,9,10-dianhydride (PTCDA) and the imide analogue PTCDI on the Ag-Si(111)square root(3) x square root(3)R30 degrees surface using scanning tunneling microscopy. We find that PTCDA forms square, hexagonal, and herringbone phases, which coexist on the surface. The existence of a square phase on a hexagonal surface is of particular interest and is a result of a near commensurability between the molecular dimensions and the surface lattice. Contrast variations across the square islands arise from PTCDA molecules binding to different sites on the surface. PTCDI on Ag-Si(111)square root(3) x square root(3)R30 degrees forms extended rows, as well as two-dimensional islands, both of which are stabilized by hydrogen bonding mediated by the presence of imide groups. We present models for the molecular arrangements in all these phases and highlight the role of hydrogen bonding in controlling this order.

The catalytic performance of Cu/ZnO/Al 2 O 3 (CuZnAl) catalyst for CO 2 hydrogenation to methanol was investigated over a period of 720 h time-on-stream, which showed that the space time yield of CH 3 OH was decreased by 34.5% during the long-term testing. Different characterization techniques, including X-ray diffraction (XRD), scanning electron microscopy, high resolution transmission electron microscopy, X-ray photoelectron spectroscopy (XPS), and N 2 O adsorption experiments, were applied to study the deactivation reasons. XRD and N 2 O adsorption experiments indicated that there were no obvious changes in Cu particle size after the CuZnAl catalyst was exposed to reaction atmosphere for 720 h, while agglomeration took place on ZnO particles. XPS results revealed that part of the metallic Cu was oxidized to Cu 2+ . The CuZnAl catalyst deactivation was proved to be due to the comprehensive effect of Cu oxidation and ZnO species agglomeration during CO 2 hydrogenation to methanol.

Selective dehydration of glycerol to value-added acrolein is an interesting catalytic process not only owing to the increasing coproduction of glycerol in the biodiesel production but also due to the emerging perspectives to provide a sustainable route for acrolein production. The use of zeolites in glycerol dehydration is a very promising way with high performance, but these microporous catalysts are often severely constrained by the rapid catalyst deactivation due to coke formation. Although the introduction of hierarchical structure in microporous zeolite crystals is believed to be an effective approach to enhance their activity and lifetime, the relationship between the mesoporosity and catalytic performance is still controversial. In this paper, four kinds of typical hierarchical ZSM-5 catalysts with diverse mesoporosity and similar microporosity/acidity are prepared by the salt-aided seed-induced route. By systematically studying their catalytic performances, the effects of various mesopore types on the glycerol dehydration are declared, including pore size, amount, distribution, and connectivity. The sample with open and interconnected mesopore architecture display the high activity, long lifetime, and improved selectivity, while the worse behavior of closed and small mesopores is attributed to the mass transfer limitations and/or the in-pore condensation of reactant or its heavier derivatives. Moreover, the combined effect of acidity and hierarchical structure was also explored by changing the framework Si/Al ratio. The findings emphasize the necessity of reasonably designing the zeolite catalysts with proper hierarchical structure and acidity for maximal catalytic advantage.

Recently, CO 2 hydrogenation for the controlled growth of the carbon chain to produce high-value C 2 or C 2+ products has attracted great interest, where achieving high selectivity for a specific product remains a challenge, especially for ethanol. Herein, we have designed a bifunctional Ir 1 −In 2 O 3 single-atom catalyst, integrating two active catalytic centers by anchoring the monatomic Ir onto the In 2 O 3 carrier. This Ir 1 −In 2 O 3 single-atom catalyst is efficient for the hydrogenation of CO 2 in liquid, yielding a high selectivity for ethanol (>99%) with an excellent initial turnover frequency (481 h −1 ). Characterization shows that the isolated Ir atom couples with the adjacent oxygen vacancy forming a Lewis acid−base pair, which activates the CO 2 and forms the intermediate species of carbonyl (CO*) adsorbed on the Ir atom. Coupling this CO* with the methoxide adsorbed on the In 2 O 3 forms a C−C bond. The strategy of this effective bifunctional single-atom catalyst by synergistically utilizing the distinct catalytic roles of the single-atom site and the substrates provides a new avenue in catalyst design for complex catalysis.

A series of Fe-based catalysts with accurately controlled amounts of Na are synthesized to investigate the relationship between the promoter and the catalytic performance for CO 2 hydrogenation to alkenes. With the increasing amount of Na, both CO 2 conversion and alkenes selectivity increase at low and moderate amounts and then plateau (with the highest to be 36.8% and 64.3%, respectively), while the corresponding methane production decreases to 7.2%. It is found that the addition of Na enhances the adsorption of CO 2 , facilitates the formation and stability of active species Fe 5 C 2 , and inhibits the secondary hydrogenation of alkenes. All these effects lead to the desirable catalytic performance. Besides, it is observed that the content of Fe 5 C 2 is related to the amount of Na. This study can provide scientific guidance to the design and the synthesis of high-efficiency catalysts for CO 2 hydrogenation to high-value chemicals.

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Addition of Mn to Na/Fe catalysts enhanced light olefin selectivity in CO2 hydrogenation through modulation of the C–C coupling reaction.