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The development of reliable catalysts with both excellent activity and recyclability for carbon dioxide (CO2) hydrogenation is challenging. Herein, a ternary hybrid heterogeneous catalyst, involving mononuclear Ru complex, N, P-containing porous organic polymers (POPs), and mesoporous hollow carbon spheres (Ru3+-POPs@MHCS) is reported for CO2 hydrogenation to formate. Based on comprehensive structural analyses, we demonstrated that Ru3+-POPs were successfully immobilized within MHCS. The optimized Ru3+-0.5POPs@MHCS catalyst, which was obtained with about 5 wt.% Ru3+ and 0.5 mmol POPs polymers confined into 0.3 g MHCS, exhibited high catalytic activity for CO2 hydrogenation to formate (turnover number (TON) > 1,200 for 24 h under mild reaction conditions (4.0 MPa, 120 °C)) and improved durability, compared to Ru3+ catalysts without POPs polymers (Ru3+-MHCS) and unencapsulated MHCS (Ru3+-0.5POPs) catalysts. The improved catalytic performance is attributed to the high surface area and large pore volume of MHCS which favors dispersion and stabilization of Ru3+-POPs. Furthermore, the MHCS and POPs showed high CO2 adsorption ability. Ru3+-POPs encapsulated into MHCS reduces the activation energy barrier for CO2 hydrogenation to formate. [ABSTRACT FROM AUTHOR]

• Pd NPs deposited on rGO layer-coated Au nanorod catalysts were synthesized. • The rGO contributes to the control of Pd NP sizes in the catalyst synthesis. • H 2 O 2 production from H 2 and O 2 is highly promoted under visible light irradiation. • SPR of Au nanorod accelerated H 2 activation, and thus enhanced H 2 O 2 production. A promotional effect of surface plasmon resonance (SPR) on direct hydrogen peroxide (H 2 O 2) formation from H 2 and O 2 over a structure-controlled Pd-Au catalytic system is reported herein. Pd NPs supported on reduced graphene oxide (rGO) layer-coated Au nanorod (NR) nanocomposite catalysts were synthesized, and the structure was confirmed by multiple characterization techniques. H 2 O 2 production is highly enhanced under visible light irradiation in the direct H 2 O 2 formation from H 2 and O 2. The H 2 O 2 decomposition test and the H 2 -D 2 exchange reaction reveal that the SPR of Au NRs facilitates H 2 activation on the Pd NP surface, leading to efficient H 2 O 2 production. Furthermore, the rGO layer not only functions as an electron mediator in the catalytic reaction, but also contributes to the control of Pd NP sizes in the catalyst synthesis. [ABSTRACT FROM AUTHOR]

Aerobic oxidative dehydrogenation of amines to imines by thiol‐modified Pd nanoparticle (NP) catalysts on carbon supports is reported herein. Whereas conventional non‐modified Pd NP catalysts are nearly inactive, the carbon‐supported Pd catalysts modified with thiol ligands efficiently catalyze the reaction with high selectivity. Kinetic studies and DFT calculations reveal that the rate‐limiting imine product desorption step is significantly boosted on the thiol ligands‐modified Pd surface compared to the non‐modified Pd surface due to the steric hindrance of the ligands. Furthermore, the catalytic activity is dramatically enhanced in the presence of both pyrene‐functionalized thiol modifiers and graphene‐based carbon supports; 96 % conversion is attained after 4 h at 110 °C. The π–π interactions between pyrene groups and the highly crystallized carbon surface suppress the leaching of ligands, which offers improved catalyst stability even under O2 atmosphere at 110 °C, thereby resulting in high activity. [ABSTRACT FROM AUTHOR]

Production of formic acid (FA) by hydrogenation of CO2 using a ternary hybrid catalyst, poly(ethyleneimine)-tethered Ir-iminophosphine complex (Ir-PN-PEI) immobilized in titanate nanotubes (TNTs), is reported. On the basis of comprehensive structural analyses, we show that Ir-PN-PEI is tightly immobilized within the cavity space of TNT without affecting the electronic/coordination states of Ir atoms. Liquid-phase CO2 hydrogenation under pressurized CO2 and H2 demonstrates that the Ir-PN-PEI catalyst immobilized in Na+-type TNT exhibits the highest FA yields (TON>1000 for 20 h under mild reaction conditions (2.0 MPa, 140 °C)) and improved reusability, which far outperform those of unimmobilized prototype Ir-PN-PEI. The improved catalytic performance is attributed to the ability of TNT to efficiently capture CO2 and to stabilize PEI, with Na+-type TNT with higher basic property providing a more productive effect. The catalyst is reusable over multiple cycles with activity comparable to those of heterogeneous catalysts previously reported, rendering this material suitable for efficient transformation of CO2 into FA. [ABSTRACT FROM AUTHOR]

One-pot reaction involving Pd-catalyzed H2O2 production from H2 and O2 and Ti-catalyzed successive oxidation with H2O2 in a single reaction vessel is an alluring strategy for the synthesis of targeted chemicals in terms of sustainability and economic competitiveness. In this study, a yolk-shell nanostructured catalyst, consisting of Pd nanoparticles (NPs) with core diameter ca. 4.0 nm and a porous titanosilicate shell of ca. 15 nm thickness, was fabricated by using an oil-in-water (O/W) microemulsion-based interfacial self-assembly approach. Compared with prototype titanosilicate-supported Pd NP catalysts and core-shell structured analogues, the yolk-shell nanostructured catalyst exhibited superior catalytic efficiency in the one-pot oxidation reaction of sulfides with 83 % H2O2 utilization efficiency, because of the productive effect of the titanosilicate shell in limiting the diffusion of H2O2 generated in situ over the encapsulated Pd NPs and the efficient access of the H2O2 to the neighboring active Ti sites. This study provides promising avenues for the development of multifunctional nanostructured catalysts that are useful for one-pot reactions. [ABSTRACT FROM AUTHOR]

Candida antarctica lipase A was immobilized on spherical silica nanoparticles with oil-filled core and oil-induced mesoporous silica shell with different silica shell structures. The immobilization of enzymes was achieved by directly adding enzymes to the oil-in-water emulsion system under ambient synthesis conditions, and the silica shell structure was controlled by the addition of the cosolvent ethanol to the initial synthesis medium. Detailed structural analysis revealed the formation of oil-filled spherical silica nanoparticles with 3.4-4.2 nm mesopores randomly arranged in the silica shell; the thickness and pore characteristics of these pores markedly changed with the addition of ethanol. The retention of the enzyme activity during biocatalysis was significantly affected by the structural properties of the silica shells, and it was found that a thick and dense silica shell is essential to afford an active, recyclable, and stable biocatalyst. Furthermore, the oil encapsulated within the core cavity was found to play an important role in achieving a high catalytic efficiency. [ABSTRACT FROM AUTHOR]

Highlights: [•] A strategy that contributes to both waste and carbon management is proposed. [•] Layered double hydroxide (LDH) compound can be synthesized from blast furnace slag. [•] The slag-made LDH efficiently catalyzes the addition reaction of epoxides with CO2. [•] The slag-derived impurity elements act as catalyst promoters. [ABSTRACT FROM AUTHOR]

Blast furnace slag (BFS), a high-volume byproduct resulting from iron-making processes, can be considered as a low-cost and abundant precursor for preparing layered double hydroxide (LDH) compounds. Here we demonstrate that a Ca-based LDH compound (hydrocalumite) synthesized from waste BFS through facile two-step procedures and its derivatives work as useful heterogeneous base catalysts for multiple chemical reactions including the Knoevenagel condensation, oxidation of alkylaromatics with O2, transesterification, and cycloaddition reaction of epoxides with atmospheric CO2. Structures were verified by using XRD and thermogravimetric analysis. The surface basicity and coordination geometry of the active metal species that substantially affect the catalytic activity were investigated by CO2-temperature programmed desorption (TPD) and X-ray absorption fine structure (XAFS) measurements, respectively. These characterization results revealed that the slag-derived impurity elements, such as Fe, Ti, and Mn, effectively act either as active sites or as catalyst promoters in particular reactions and that the kind of guest counter anion (Cl− or NO3−) also plays a key role for achieving high catalytic efficiencies. In any reaction, the catalyst was easily separated by filtration and recyclable in multiple catalytic runs with retention of its activity and fine selectivity, irrespective of its considerable impurity level. It is believed that the slag-made hydrocalumite can replace existing LDH catalysts as a low-cost alternative and potentially contribute to sustainable chemical processes. [ABSTRACT FROM AUTHOR]

Keywords: Dehydrogenation; Heterogeneous catalysis; Pd nanoparticles; - interaction; Surface modification EN Dehydrogenation Heterogeneous catalysis Pd nanoparticles - interaction Surface modification 5834 5834 1 12/07/20 20201204 NES 201204 B The Front Cover b shows Pd nanoparticle catalysts modified with pyrene-thiol ligands on carbon supports for aerobic oxidative dehydrogenation of amines to imines. In their Communication, T. Yoshii et al. experimentally and theoretically demonstrate that the rate-limiting imine product desorption is boosted as a result of the steric hindrance of the ligands, and the catalytic stability is significantly improved by the - interactions between catalyst and support, which make this material an active and stable catalyst for the amine dehydrogenation reaction. Dehydrogenation, Heterogeneous catalysis, Pd nanoparticles, - interaction, Surface modification. [Extracted from the article]

The Front Cover shows the production of formic acid from CO2 and H2 by a ternary hybrid catalyst composed of an Ir complex, poly(ethyleneimine) and titanate nanotubes (TNTs).In their Full Paper, Y. Kuwahara et al. demonstrate that immobilization of a poly(ethyleneimine)‐tethered Ir complex catalyst inside the cavity space of TNTs can afford efficient catalysts with both improved activity and reusability, owing to the CO2 adsorption capacity of poly(ethyleneimine) and stabilizing effect of TNTs. This study can potentially offer a generalized method to capture and convert CO2, which is particularly desirable for sustainable formic acid production. More information can be found in the Full Paper by Y. Kuwahara et al. on page 1906 in Issue 11, 2017 (DOI: 10.1002/cctc.201700508). [ABSTRACT FROM AUTHOR]

This work presents the synthesis of Pd-loaded microporous titanosilicalite-1 (Pd/TS-1) and Pd-loaded hierarchical titanosilicalite-1 (Pd/HTS-1) with abundant mesopores (2–30 nm) inside the framework via hydrothermal method using polydiallydimethyl ammonium chloride as the non-surfactant mesopore template. XRD, N 2 sorption, FT-IR, FESEM-EDX, TEM, XPS, and DR-UV techniques were used to characterize the morphological and physicochemical properties of the synthesized materials. These materials were tested as heterogeneous catalysts, along with tetrapropylammonium bromide as co-catalyst, for cycloaddition reactions of CO 2 with epoxides to produce cyclic carbonates. It was found that the epoxide conversions were influenced by acidity and pore accessibility of the catalysts. Using Pd/HTS-1 facilitated bulky substrates to access active sites, resulting in higher conversions than Pd/TS-1. Over 85 % conversions were achieved for at least five consecutive cycles without significant loss in catalytic activity. The interaction between the Pd active surfaces and epichlorohydrin (ECH) was further studied by DFT calculations. The existence of Pd(200) was more influential on adsorbing epichlorohydrin (ECH) and subsequent formation of dissociated ECH (DECH) intermediate than Pd(111) surface. However, Pd(111) was dominant in enhancing the activity of DECH species for capturing CO 2. Therefore, the co-existence of Pd(200) and Pd(111) surfaces was needed for cycloaddition of CO 2 with ECH. [Display omitted] • Novel Pd/HTS-1 showed high potential for catalyzing CO 2 cycloaddition with epoxides. • Catalyst had enhanced Lewis acid sites and high accessibility to HTS-1 active sites. • Effects of Pd surface on its interaction with ECH were investigated computationally. • Pd(200) and Pd(111) surfaces were proven to promote adsorption of ECH to capture CO 2. [ABSTRACT FROM AUTHOR]

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