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Hydrogen spillover is an important theme for hydrogen storage and H-involving catalytic reactions. This work shows that catalytic reactivity and selectivity can be revealed by differentiating the energetic characteristics of spilled H species. With the assistance of Ti, F and C in MXenes, Pd1.8Ni@Ti3C2Txpresents a high capacity for spillover hydrogen storage at ambient temperatures, and the rich oxygenated groups act as the main carriers of hydrogen spillover around metal nanoparticles. Thermodynamic analysis reveals that the catalytic performances are energetically dominated by the adsorption enthalpies of the active spilled H species rather than the amount of spillover hydrogen, and can be tuned by alloying and surface modification. The ideas are verified from the excellent catalysis, chemoselectivity and stereoselectivity of Pd1.8Ni@Ti3C2Txin semihydrogenations. The strategy of maximizing catalytic performances is applicable to other Pd-based bimetals@Ti3C2Tx, such as Pd2.6Co@Ti3C2Txand Pd1.5Fe@Ti3C2Tx, and provides new energetics perspectives to understand the catalytic mechanism in spillover-involving chemical procedures.

Sluggish sulfur conversion kinetics pose an ongoing challenge in lithium-sulfur batteries (LSBs). Here, we present a solution through far-reaching long-range electronic regulation (LRER) on single-atom active sites. N-doped carbons (Co-NC) are implanted with densely-distributed Co single atoms, and supported on Ti3C2TxMXene substrates to assemble 3D Co-NC/MXene catalyst. MXene effectively mediates interlayer charge transfer (∼0.70 |e|) contrasted with popular carbon materials (∼0.06 |e|) to produce LRER through surrounding carbon atoms. The synergy of LRER with near-range electronic regulation (NRER) tunes electronic structures, and enhances heterostructural stability, thus provoking desirous catalytic kinetics of Co single atoms in sulfur reduction. Thereby, the Co-NC/MXene/S cathodes exhibit impressive rate performance and excellent cycling stability (only 0.015% capacity decay per cycle over 600 cycles at 4 C) in LSBs, surpassing state-of-the-art sulfur cathodes. This work reveals the importance of LRER for improved catalysis, and provides new guidance to tailor heterostructures to achieve high-efficient catalysts in various process.

The nanoplasmonic metal-driven photocatalytic activity depends heavily on the spacing between metal nanoparticles (NPs) and semiconductors, and this work shows that ethylene glycol (EG) is an ideal candidate for interface spacer. Controlling the synthetic systems at pH 3, the composite of Ag NPs with EG-stabilized amorphous TiO2(Ag/TiO2-3) was synthesized by the facile light-induced reduction. It is verified that EG spacers can set up suitable geometric arrangement in the composite: the twin hydroxyls act as stabilizers to bind Ag NPs and TiO2together and the nonconductive alkyl chains consisting only of two CH2are able to separate the two building blocks completely and also provide the shortest channels for an efficient transfer of radiation energies to reach TiO2. Employed as photocatalysts in hydrogen evolution under visible light, amorphous TiO2hardly exhibits the catalytic activity due to high defect density, whereas Ag/TiO2-3 represents a remarkably high catalytic efficiency. The enhancement mechanism of the reaction rate is proposed by the analysis of the compositional, structural, and optical properties from a series of Ag/TiO2composites.

The selective semihydrogenation of alkynes is of importance in many industrial applications, but great challenges still remain in the full utilization of noble metals for the catalysis of hydrogen spillover on mixed supports. As Pd0is chemically loaded on Cu2O/TiO2, this work reports that Pd0is imparted with a high electron density to dissociate H2efficiently and the active Cu2O hydride is responsible for the high catalytic activity in spillover semihydrogenations. As compared with inert Pd–Cu2O/SiO2interfaces, the studies demonstrate that the high chemoselectivity and stereoselectivity originate from the well-defined p–n junctions of Cu2O/TiO2, therein alkynes are adsorbed in their transconfigurations and the product is desorbed from them. As catalyzed by 1.3Pd–3.6Cu2O/TiO2in 1 atm H2at 30 °C, the semihydrogenations can be completed in 90 min with 97.6% chemoselectivity for phenylacetylene, and in 45 min with 92.4% stereoselectivity for methyl non-2-ynoate. These studies provide new ideas to design and synthesize noble metal-based catalysts through manipulating the interface properties of the mixed supports.

In recent years, metal–organic frameworks (MOFs) have been explored as emulsifiers for the fabrication of Pickering emulsions and then used for hybrid material synthesis and interface catalysis. Nevertheless, stimuli-responsive Pickering emulsions stabilized by MOFs have been rarely reported so far, although they are of great importance for fundamental research studies and practical applications. Herein, for the first time, triethylenetetramine (TETA)-functionalized MOFs (ZIF-90/TETA) have been designed, synthesized, and used for fabricating CO2-/N2-response Pickering emulsions. It is shown that even at the ZIF-90/TETA content of 0.25 wt %, the functional MOF can still efficiently emulsify n-hexane and water to form a high internal phase Pickering emulsion. Importantly, the Pickering emulsion can be easily and reversibly switched between emulsification and demulsification by bubbling of CO2and N2alternatively at atmospheric pressure. The possible mechanism of the CO2/N2switchable emulsion is investigated by zeta potential, water contact angle, interfacial tension, 13C NMR spectroscopy, and an optical microscope. It is found that the acid–base reaction of CO2with TETA anchored on the surface of ZIF-90 leads to the production of hydrophilic ammonium bicarbonate and carbamate, which results in the emulsification of the Pickering emulsion. However, when N2is bubbled to remove CO2, the reverse reaction takes place to cause the demulsification of the Pickering emulsion. Moreover, the CO2/N2switchable Pickering emulsion has been successfully used as a microreactor for Knoevenagel reactions to demonstrate a highly efficient integration of chemical reaction, product separation, and ZIF-90/TETA recycling for a sustainable chemical process.

In this study, hot compression tests of (Cu43Zr48Al9)98Y2bulk metallic glasses (BMGs) were performed, and their microstructure and thermal properties after the deformation were studied to explore the appropriate range of their optimum processing parameters. The experimental results show that the superplastic deformation of (Cu43Zr48Al9)98Y2bulk metallic glasses depends mainly on the temperature and strain rate. It is suitable for superplastic processing when the alloys are in the state of Newtonian flow and do not crystallise. The appropriate processing parameters of (Cu43Zr48Al9)98Y2BMGs are the temperatures and strain rates, which are below the “dividing line”. And when the temperature is above 733 K, the strain rate must be >1 × 10−3 s−1.