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4-Nitrophenol (4-NP) usually exists in soil and groundwater, which causes great harm to the environment and human health.

The RuO2-decorated MoS2 nanosheets obtained by interface modifications act as an excellent electrocatalyst for alkaline hydrogen evolution reactions.

Controlling the spatial confinement effect and highly dispersed Pd nanoparticles (NPs) can help to improve applicability in catalysis, energy conversion, and separation. However, the nonspatial confinement effect, agglomeration of Pd NPs of catalyst and harsh reaction conditions have become the urgent problems to be solved in Suzuki-Miyaura cross-coupling reaction. Herein, we report the first application of a new MOFs@COFs by using core with metal organic frameworks (MOFs) NH2-MIL-101(Fe) and shell with covalent organic frameworks (COFs) for loading Pd NPs. The quickly formation of a transition state, the highly dispersed Pd NPs and the advancedly spatial confinement effect were achieved by coupling Fe base synergistic active components, electron-oriented anchoring with controlling pore scale, respectively. Most notably, as a proof-of-concept application, the high catalytic activity of NH2-MIL-101(Fe)@Pd@COFs(3 + 3) in catalysis is elucidated for Suzuki-Miyaura coupling reaction by the broad scope of the reactants and the preeminent yields of the products, together with excellent stability and recoverability. With this strategy, the mechanism of Suzuki-Miyaura coupling reaction was verified by examining the catalytic activity. We hope that our approach can further facilitate the study of the design and use of functional MOFs@Pd@COFs materials.

MoS2/NiS flower-like heterostructures are prepared via precise interface modification for enhancing the intrinsic catalytic activity toward the HER.

Carbon nitride, considered to be a promising photocatalyst, still has much room to increase the catalytic performance owing to the slow charge transfer and limited light harvesting ability. Herein, carbon doping carbon nitride with hollow tubular structure was successfully developed by using melamine and sodium alginate as precursors via a simple hydrothermal calcination method. The effects of carbon content on the structure and photocatalytic activities of as-obtained carbon nitride were researched in detail. The hollow tubular structure can assist the enhancement of specific surface area, increase of visible light harvesting ability and enhancement of electron transport ability. Simultaneously, carbon doping can adjust the photoelectric performance and band structure of carbon nitride due to the generation of delocalized big π bonds to enhance the photocatalytic activities. The catalytic performance of as-obtained carbon nitride is estimated by hydrogen evolution reaction. And carbon doping carbon nitride with hollow tubular structure accounts for 3 times and 2 times promotion than pristine CN in hydrogen evolution rate under λ > 420 nm and λ > 400 nm, respectively. Especially, the sample CN-40 shows a highly enhanced hydrogen generation efficiency of 1210.3 μmol h-1 g-1, which should be inseparable from the function of carbon doping and hollow tubular structure.

The sugarcane woolly aphid is one of the main pests of sugarcane worldwide. The Pinellia pedatisecta agglutinin (PPA) gene has been demonstrated to function towards aphid resistance in other crops. In our study, in order to investigate the PPA function towards aphid control in sugarcane and its underlying mechanism, the PPA gene was overexpressed in a sugarcane Zhongzhe 1 (ZZ1) cultivar in independent transgenic sugarcane lines. It was confirmed in this study that PPA transgenic sugarcane can resist aphids via detecting the aphids’ development and tracing the survival number on PPA−transgenic sugarcane lines as well as PPA negative control lines. The mechanism of PPA lectin−associated defense against aphids was preliminarily explored. Stomatal patterning differences of sugarcane leaves between PPA−transgenic sugarcane lines and negative control lines were found. PPA overexpression led to an increase in stomata number and a decrease in stomata size that might have changed the transpiration status, which is critical for aphids’ passive feeding. Moreover, the antioxidant enzyme, sugar, tannin and chlorophyll content in sugarcane leaves before and after aphid infestation was determined. The results indicated that PPA overexpression in sugarcane resulted in an increase in antioxidant enzyme activity and tannin content, as well as a reduction in the decline of certain sugars. These together may improve sugarcane resistance against the sugarcane woolly aphid.

In this study, we synthesized a series of Ni-based catalysts with different CeO2 contents (0, 1, 2, 5 and 10 wt%) anchoring on the Al-Mg oxide spheres (AMO) with three-dimensional hollow flower-like structure. The triethoxyoctylsilane (TEOOS) and polyvinylpyrrolidone (PVP) were selected as effective modified reagents to introduce hydrophobic functionality on the surface of AMO and Ni-CeO2 nanoparticles, respectively, for controllable anchoring Ni-CeO2 nanoparticles on AMO by hydrophobic interaction driving mechanism. The effects of CeO2 content on the texture, dispersion of Ni species, the reducibility of Ni2+, surface electronic states and acidity were investigated in detail. The Ni-5CeO2/AMO was found to achieve the highest 2,2′-bipyridine selectivity of 90.6% and maximum turnover number (TON) of 8611, specifically. Moreover, the Ni-5CeO2/AMO exhibits superior stability, maintaining 89% of 2,2′-bipyridine yield after 6 runs, due to the mitigated nickel leaching and promotion of the desorption of 2,2′-bipyridine. Furthermore, with the help of DFT calculations, a possible reaction mechanism was discussed and illustrated.

Transition metals are increasingly attracting interest in electrocatalysts for use in water decomposition due to their excellent catalytic activity and stability. Simultaneously, metal-organic frameworks with designable metal ion centers and organic ligands are the promising precursors for the one-step synthesis of metal encapsulated in carbon composites for alkaline hydrogen evolution reaction (HER). Herein, we report the successful construction of Co-CoO/ZnFe2O4 encapsulated in carbon nanowires (Co-CoO/ZnFe2O4@CNWs) by annealing as-synthesized nanowire Co/Zn/Fe-MOF at 400 °C in N2. This structure provides the rich defect sites and active centers, and the synergy of Co, CoO and ZnFe2O4 lead to efficient hydrogen evolution when the composite is used as a catalytic electrode for HER in 1.0 M KOH. The catalyst shows a low initial overpotential (97 mV) and a small Tafel slope (138 mV dec−1), and the overpotential at 10 mA cm−2 is only 226 mV. In addition, this composite material exhibits excellent long-term durability even after 1000 cycles. It is expected that it is a potential alternative catalyst for rational utilization in the field of electrolytic water decomposition.

Fe-doped mesoporous alumina (MA) was successfully synthesized via a facile one-pot synthesis method. The resulting Fe-doped MA samples possess typical mesoporous structure, relatively high BET surface area, and narrowed pore size diameter. Besides, the iron species are well-dispersed in the alumina matrix, and more importantly, some small oligonuclear iron oxide clusters are linked on the surface of alumina, leading to the elimination of strong acid sites. The reaction of phenol hydroxylation was preceded at room temperature for 2 h. The introduction of mesoporous structure in alumina would be favorable for the adsorption and diffusion process of reactant and product molecules, and also the well-dispersed iron species in alumina matrix and large amount of acid sites stimulate more active hydroxyl radicals which are greatly beneficial for the catalytic process, especially the elimination of strong acid sites would inhibit the over-oxidation reaction. In this case, the sample of 5Fe–MA displays the best catalytic performance especially with the extremely high dihydroxybenzene selectivity of 93.2%, and the good catalytic stability is also evidenced by the five times recycling tests. In this work, the Fe-doped mesoporous alumina (MA) was successfully prepared. The iron species are well-dispersed in the alumina matrix, and some small oligonuclear iron oxide clusters are linked on the surface of alumina, leading to the elimination of strong acid sites. The advanced properties of mesoporous structure, well-dispersed metal active centers and lack of strong acid sites in Fe-doped MA are greatly beneficial for the catalytic process, especially for the dihydroxybenzene selectivity with extremely high value of 93.2%.

New catalysts based on polymeric ionic liquids were synthesized and applied into selective oxidation of benzyl alcohol. Polymeric ionic liquid microspheres (PILM) were prepared by radical polymerization, and then the cations in the imidazole ring were exchanged with the metal anions. After that, the metal anions were reduced to Pd nanoparticles that was supported on the surface of PILM. This metal loading method favored the maximum amount of supported Pd nanoparticles that were uniformly distributed on the surface of PILM. In addition, the introduction of CeO2 prevented the aggregation of Pd nanoparticles and finally formed PILM/Pd/CeO2 catalysts with a core-shell structure. The performance of the PILM/Pd/CeO2 catalysts was evaluated by changing the [K2CO3] : [alcohol] molar ratio, reaction temperature and oxygen flow rate in the oxidation reaction of benzyl alcohol. The conversion and selectivity under the optimal reaction conditions reached 48% and 98% respectively The catalysts were effective and reusable after 5 cycles of experiments. In the end, a mechanism underlying the reaction pathway in benzyl alcohol oxidation was put forward.

Enhancing the kinetics of electrocatalytic water splitting, including the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), under alkaline conditions is of key importance for producing high purity and renewable hydrogen on a large scale. Owing to their unique structural features, two-dimensional (2D) heterostructures have been regarded as promising next-generation electrocatalysts for overall water splitting. Herein, we successfully synthesized three-dimensional (3D) flower-like Co–Ni–P/MoS2 heterostructural hybrid spheres assembled from heterostructural 2D nanosheets. Benefiting from well-exposed interfaces and favorable diffusion channels, the as-prepared 3D flower-like Co–Ni–P/MoS2 heterostructural hybrid spheres manifest excellent overall water splitting performance in an alkaline solution with a low Tafel slope of 71 and 41 mV dec−1 for oxygen and hydrogen evolution reactions, and show significantly improved long-term durability. Furthermore, the 3D flower-like Co–Ni–P/MoS2 heterostructural hybrid spheres used in both the anode and cathode show a low cell voltage of 1.53 V at a 10 mA cm−2 current density. Using DFT calculations, we found the outstanding chemisorption of hydrogen and oxygen-containing intermediates making Co–Ni–P/MoS2 heterostructures an efficient bifunctional overall electrochemical water splitting catalyst. In summary, this work opens up an important direction for exploring efficient and durable bifunctional electrocatalysts for the overall water splitting.

We report a facile one-pot solvothermal synthesis of NiPd alloy homogeneously encapsulated between reduced graphene oxide sheets and N-doped carbon layers (rGO@NiPd@NC) with sandwich structure. In this study, dopamine served as both carbon-nitrogen source and green reagent, which cannot only form N-doped carbon layers encasing metal nanoparticles through high-temperature roasting but also co-reduce metal ions to form NiPd alloy. The rGO@NiPd@NC nanocomposite exhibits enhanced hydrogen evolution reaction (HER) activity with a small overpotential of 56 mV at 10 mA cm−2 and a Tafel slope approaching 33 mV dec−1 in acidic aqueous media, which are similar to the HER activity of commercial Pt/C catalyst (52 mV at j = 10 mA cm−2; Tafel slope, 31 mV dec−1). Additionally, the electrocatalyst which reveals excellent electrochemical stability is reflected in that the polarization curve shows negligible difference after 1000 cycles and the current density only slightly decreases within 20 h test, providing more possibilities for practical application in the future.

Achieving sustainable energy technology with outstanding performance and clean materials for overall water splitting, while fascinating, still include many challenges. Herein, the masterly CoNi2S4@CoS2/NF 3D microspheres assembled by peapod-like nanorods with a mass of CoS2 particles are successfully prepared on nickel foam. The well-preserved 3D porous materials with unique heterostructure have various merits including more electronic channels, small electrons transfer resistance and open interior space. Besides, the unique peapod-like structure endows the catalyst plentiful, dispersive and exposed reactive sites, which is vital important to significantly increase the electrochemical performance. Notably, the as-prepared CoNi2S4@CoS2/NF catalysts achieve optimized electrocatalytic activity for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) at low overpotentials of 259 mV and 173 mV while deliver 10 mA cm−2 current density, respectively. It can be anticipated that it is a potential alternative catalyst for rational utilization in electrolytic water splitting fields.

A core-shell structure Au-based catalysts mSiO2/Au/Co3O4 HS were successfully derived from in-situ growth ZIF-67 hollow spheres, which were synthesized by a one-step soft template method. The samples were characterized by SEM, TEM, EDX, XPS, XRD and BET to confirm its successful preparation and structural features. The catalytic performance of the catalysts were evaluated by liquid phase oxidation of benzyl alcohol to benzaldehyde with O2 as the oxidant under alkaline conditions. The experimental results illustrated that reaction conditions, including effect of catalyst amount, oxygen flow rate, reaction temperature and reaction time, were optimized to be 40 mg, 50 ml/min, 140 °C and 5 h, respectively. Meanwhile, 55% conversion of benzyl alcohol and 84% selectivitiy to benzaldehyde together with the excellent reusability and stability were achieved under optimal reaction conditions, which was attributed to the core-shell structure leading to the encapsulation of Au NPs and provision of multiple active reaction interface. Based on the intermediates formed from the de-protonation of substrate, a plausible oxidation reaction mechanism with mSiO2/Au/Co3O4 HS catalysts was tentatively proposed to study the relationship between structure and catalytic performance.

A facial, template-free and green strategy was developed to prepare C-doped hollow spherical g-C3N4 derived from supramolecular self-assembly of melamine, glucose and cyanuric acid. Especially, the precursors were tightly connected by hydrogen bonds, wherein glucose was served as a source of doped carbon. Spectroscopic and electrochemical analysis confirmed that the endmost nitrogen was replaced by the doped carbon to combine two melon parts, leading to the possible existence of the delocalized big π bonds in the system. Moreover, the GCN-x not only maintained the excellent properties of the hollow sphere, such as high surface area, moderate porosity and short charges diffusion distance, but also overcame the drawbacks of low visible light response and high electron-holes recombination rate from bulk g-C3N4. Thereby, the visible light utilization rate and the photogenerated electron-holes separation efficiency of the catalyst were improved. The highest hydrogen yield of 305 μmol h−1 from GCN-0.2 was 28.5 times that of bulk g-C3N4. Finally, a possible mechanism underlying the photocatalytic performance of C-doped g-C3N4 hollow spheres was proposed tentatively.

Herein, 3D hollow-sphere structure graphitic carbon nitride (g-C3N4) with large specific surface area and high porosity is synthesized through a mild, heat polymerization, template-free route. The as-prepared hollow-sphere structure can be used as a substrate material for uniformly dispersing Pd nanoparticles to enhance the absorption of visible light and expose more active sites. Pd nanoparticles as electron acceptor are implanted into g-C3N4, which increases the trapping capability of capturing transition electrons to gain more photogenerated carriers participating in surface reactions. Therefore, the estimated charge separation lifetime of Pd/SCN (10 h) investigated by transient absorption spectroscopy was 1.4 ns ± 338.0 ps, which is only half of SCN. Benefiting from the unique structure and the excellent optical performance, the obtained Pd/SCN composites exhibited prominent photocatalytic hydrogen evolution performance under visible light irradiation. Especially, the photocatalytic hydrogen rate of Pd/SCN (10 h) reached 267.9 µmol/h, almost 10 times higher than the Pd/2D g-C3N4. Simultaneously, a possible mechanism for photocatalytic H2 reaction was proposed based on the characterization results.

As one of the ideal catalysts, noble metal materials can realize the conversion from benzyl alcohol to benzaldehyde. However, in previous reports, the loss of surface noble metal is one of the important reasons for the decrease in reaction performance. Here, a simple method was reported for stepwise fabrication of SiO 2 @Co 3 O 4 /Au@m-SiO 2 catalysts with core–shell structure. On the one hand, the core–shell structure provided abundant reaction sites for the oxidation of benzyl alcohol to benzaldehyde. On the other hand, the outer layer of m-SiO 2 effectively prevents the loss of Au nanoparticles. In this process, we studied the effects of multiple factors on the target reaction by controlling a single variable. The experimental results show that under the optimal conditions (the catalyst dosage, reaction temperature, reaction time and O 2 flow rate are 40 mg, 160 °C, 6 h, 60 ml/min, respectively), the conversion rate of the target reaction reaches 58% and the selectivity is as high as 82%. In the end, a mechanism was put forward to illustrate the underlying reaction pathway in benzyl alcohol oxidation.

Herein, a novel strategy is established to synthesize Mo-doped graphitic carbon nitride (g-C3N4) with excellent photocatalytic activity through a green approach of biological template. The addition of biotemplates provides a microenvironment for the formation of hydrogen bonds in which the flower-like g-C3N4 is formed by self-assembly between precursors, which not only increases the specific surface area of the material but also exposes more catalytic activity edge. Benefiting from the non-localized of Mo(VI) 4d orbital, Mo-doped g-C3N4 constructs a suitable band structure and a built-in electric field that promotes electron delocalization, which improves the absorption range of visible light and separation efficiency of photo-generated electron-hole pairs. Subsequently, a possible chelation-hydrogen bond coordination mechanism was proposed based on the characterization results of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR) and 15N solid-state NMR (15N NMR). As a result, the π-conjugated system of g-C3N4 was extended by forming a chelate centered on Mo(VI). Photocatalytic hydrogen evolution (PHE) showed that the optimal hydrogen evolution rate of Mo-doped g-C3N4 was as high as 2008.9 umol/g·h, which was 9.6 times than that of bulk g-C3N4.

Hydrogen is a source of sustainable and clean energy poised to replace fossil fuels. Bifunctional electrocatalysts are actively pursued to simultaneously drive the two key reactions, hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), for hydrogen production by electrolysis water. One of the most promising candidates based on bimetallic layered double hydroxide salts (LHSs) and cobalt-based organic framework (ZIF-67) suffer from poor interface coupling. Herein, we present a new approach based on fusing NiCo LHSs nanowire arrays with ZIF-67 to fabricate three-dimensional flower-like structures on a Ni-Fe foam support. To improve interfacial coupling and catalytic performance, simple oxidation, carbonization, sulfurization, and selenization are performed to study the effects of different post-treatments and discover the optimum bifunctional electrocatalysts. The optimized S-doped catalyst reveals the highest electrocatalytic characteristic quantified by the low overpotentials of 170 and 100 mV for OER and HER at 10 mA cm -2 in 1 M KOH, respectively. This outstanding electrocatalytic property is ascribed to strong interfacial coupling between the NiCo-LHSs and ZIF-67 derivatives, as well as the rational electronic structures, dense catalytic active sites, and large specific surface area. This work opens new prospects for fabricating efficient and low-cost electrocatalysts for renewable hydrogen energy production.

The exploration of high-efficiency electrocatalysts for the hydrogen evolution reaction (HER) is of great significance for sustainable energy conversion applications, yet it remains a grand challenge. Herein, a facile and rapid strategy to synthesize ultrafine PtNi nanoparticles (NPs) anchored on N-doped graphene (rGO(N)) (labeled as PtNi/rGO(N)) at room temperature is demonstrated. (3-Aminopropyl) triethoxysilane (APTES) is selected as an effective nitrogen source to form two kinds of nitrogen (doping N and amine N) simultaneously for fabricating a rGO(N) matrix during the chemical reduction process. Benefiting from the bimetallic synergistic effect and strong metal–support interactions, this composite is expected to accelerate H+ adsorption and H2 desorption and reduce the transport resistance of electrons and hydrogen intermediates. As a consequence, the PtNi/rGO(N) with ultralow Pt loading amount (1.2 μg per electrode area (cm2)) exhibits extraordinary catalytic activity with a small overpotential of 98 mV at a current density of 10 mA μgPt−1 and an exceptional Tafel slope of 42.7 mV dec−1 for HER, exceeding the incumbent commercial Pt/C catalyst. Moreover, the PtNi/rGO(N) also displays excellent stability with negligible current degradation during a continuous operation for 20 h. The present work would be proposed as an elegant platform toward the exploration of efficient HER electrocatalysts for various renewable energy conversion applications.

Herein, a novel strategy was proposed for the fabrication of hierarchical porous silica materials templated by a poly ionic liquid (PIL, a copolymer of 1-butyl-3-vinylimidazolium bromide and acrylamide) and P123 (PEO20PPO70PEO20). The PIL acts as a co-solvent as well as a co-template in the system. The effects of the concentration of the PIL and pH on the morphology and structure of silica materials were systematically investigated. Hierarchical porous silica materials were characterized by X-ray diffraction, N2 adsorption–desorption, transmission electron microscopy and Fourier transform infrared (FTIR) spectroscopy. Moreover, the results demonstrated that the porous silica materials were equipped with a dual-mesoporous channel structure and possessed a high surface area and large pore volumes up to 1274 m2 g−1 and 1.41 cm3 g−1, respectively. Furthermore, a high-performance catalyst-based supported ionic liquid phase (SILP) was obtained by surface modification with the IL (1-(tri-ethoxy-silyl-propyl)-3-methylimidazolium chloride) of the carrier and anion exchange with HPW. Catalytic performances were investigated in the alkylation of styrene with o-xylene. Moreover, it was found that the as-synthesized catalysts showed high catalytic performance in terms of styrene conversion and selectivity to 1-phenyl-1-xylyl ethane (PXE). Specifically, the catalyst PIL-1.0g-2-IL-HPW showed excellent activities in both the yield (91.5%) and selectivity (96.8%) for this alkylation reaction.

Cross-linked poly acidic ionic liquids (MPM-C6V-SO3CF3-IL) with mesoporous and macroporous network structure have been synthesized in different solvents. The novel solid acid catalyst with special network structure has a large surface area (103.83 m2/g), large pore volume (0.72 cm3/g) and abundant mesopores and macropores, which help to improve the contact between active site and reactants. Catalytic performance of catalyst was investigated through alkylation of o-xylene and styrene. Different reaction parameters specifically solvent on obtained catalyst and production of PXE were systematically investigated. Under optimal reaction conditions (reaction time was 3 h, reaction temperature was 120 °C, catalyst amount was 0.17 g (0.5 wt%), and o-xylene/styrene mass ratio was 7.5:1), a high conversion of styrene (100%) and 1,2-diphenylethane (PXE) yield of 99.67% was obtained, which is superior to commercial acid in liquid and even previous acids synthesized by our own group. Moreover, catalyst could keep relatively high thermostability under reaction and are easy to be separated and recycled from the solution, which are critical for heterogeneous solid catalysts. Thus, this novel catalyst can be potentially applied in other acidic reactions.

A new material, MgAl-LDHs/Al2O3 fiber (abbreviated as MAF), was prepared using the classical hydrothermal method with a modification in this paper. The influence of different pH values on the structure and catalytic performance of catalysts for propane dehydrogenation was studied. The as-prepared materials were characterized by XRD, SEM, TEM, SAED, N2-physisorption, NH3-TPD, and TPO. Experimental results show that the pH value of the solution directly controlled the vertical growth of LDH sheets on Al2O3 fibers. After the suitable growth of LDH sheets, the dispersed state of active metal Pt was improved and the sizes were stabilized successfully at high temperature. Due to the effect of these LDH sheets, the BET surface and the regular pore system of the PtSn/15MAF catalysts were enhanced compared with the PtSn/CPMA catalysts. Finally, the propane dehydrogenation performance indicates that, when the pH was equal to 8.5, the catalysts (PtSn/15MAF) showed the highest conversion, selectivity and stability.

A novel thermal exfoliation strategy has been proposed to synthesize high-quality Ag/TiO2 head–body nanosnowman nanoparticles (AgTiNPs, with the head and body being single Ag and TiO2 nanoparticles, respectively) for the first time. The obtained samples were characterized with transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS) and photoluminescence (PL) emission spectra, etc. Results show that loaded Ag nanoparticles could exfoliate with a part of an adjacent caducous TiO2 nanosheet during calcination treatment, thereby fabricating high-quality Ag/TiO2 head–body nanosnowman nanoparticles. The prepared AgTiNPs show a uniform particle size, a high dispersion and enhanced interactions between Ag heads and TiO2 bodies. Compared with calcined Ag/DHS, AgTiNPs exhibit an enhanced photocatalytic performance in the degradation of RhB and solar H2 production due to improved charge carrier separation. The proposed thermal exfoliation strategy might open up a new method for the fabrication of other semiconductor–metal nanosnowman nanoparticles with enhanced photochemical properties.

In this work, silica nanoparticle-covered cross-linking graphene oxide (GOES) was successfully synthesized in a stacking graphene oxide (GOE) solution where ethylenediamine (EDA) was used for simultaneous reduction and functionalization of the graphene oxide (GO). The GOES-filled thermoplastic polyurethane (TPU) composites were prepared through solution mixing and the mechanical properties of GOES/TPU were systematically investigated. The results revealed that the properties of composites filled with the cross-linked (GOE, GOES) filler are better than those of un-cross-linked (GO, GOS) filler. Furthermore, with a loading of 2 wt%, the tensile strengths and the tensile strains of GOES/TPU composites were significantly enhanced (48.9 MPa, 2140%), as compared to pure TPU (30.6 MPa, 1370%). The improvement in mechanical properties of GOES/TPU is attributed to the homogeneous dispersion of GOES in the TPU matrix and the strong interfacial interactions between them.

We report herein the successful design of novel Au-assembled heterostructural yolk-shell magentic ellipsoids (Fe2O3 CeO2/Au/H-mC) through a facile and rational synthetic strategy. These target products comprised magnetic Fe2O3 CeO2 spindles, mesoporous carbon shells and well-dispersed sub-2 nm Au nanoparticles. Firstly, double-layered SiO2/polymer resin composites were uniformly coated on Fe2O3 CeO2 spindles in a single step via the surfactant-free extended Stober route. Subsequent carbonization-hydrothermal etching was conducted for the formation of movable magnetic hybrid metal-oxide cores within mesoporous carbon hollow shells to achieve hierarchical Fe2O3 CeO2/carbon yolk-shell magnetic architectures. Finally, by inducing the low-temperature H2 reduction combined with the [Au(en)2]3+-mediated deposition-precipitation method, abundant ultrafine Au nanoparticles were in situ synthesized within these modulated ellipsoids, displaying incredible thermal stability and dispersibility due to the stabilization effect of capped ethylenediamine ligands. Impressively, taking advantages of unique heterostructural characteristics for strengthened composite synergies and electronic interactions, these Fe2O3 CeO2/Au/H-mC ellipsoids as powerful nanoreactors manifested the merits of superior catalytic performance, feasible recovery and excellent reusability for efficient reduction of 4-nitrophenol and organic dyes under mild conditions. The synthetic protocol can be instructive for the creation of other high-efficiency nanocatalysts with complex multifunctional architectures.

In this work, we report a feasible approach to synthesize a ternary nanocomposites, Pt/lanthanum doped mesoporous zirconium oxide (Pt/La2O3-ZrO2), via an effective two-step method. Ordered mesoporous La2O3-ZrO2 composites were firstly fabricated with mesoporous silica KIT-6 as a hard template. Subsequently, uniform Pt nanoparticles encapsulated by 4 hydroxyl-terminated poly (amidoamine) (G4-OH PAMAM) dendrimers were deposited on the La2O3-ZrO2 composites. The as-prepared samples were characterized by transmission electron microscope (TEM), N2 adsorption-desorption isotherm analysis, energy dispersion X-ray analysis (EDX), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and temperature programmed reduction (H2-TPR). The average size of PtDENs was found to be 1.48nm in diameter. Furthermore, the introduction of La could improve the structure of the supports which was confirmed by XRD and H2-TPR analysis. The reduction of p-nitrophenol to p-aminophenol by NaBH4 was utilized to evaluate the catalytic performances of catalysts. Results indicated that the Pt/La2O3-ZrO2 catalyst calcined in nitrogen at 550°C exhibited the highest catalytic performance and still kept the high catalytic activity even after six cycles. This phenomenon suggests that synergistic effect among Pt-Zr-La could enhance the catalytic efficiency. Finally, reaction mechanism was proposed for the reduction of p-nitrophenol.

A novel binary-metal-oxide-coated hollow microspheres-titanium dioxide-zirconium dioxide-coated Au nanocatalyst was prepared via a facile hydrothermal synthesis method. SEM, TEM, EDX, FTIR, XRD, UV-vis and XPS analyses were employed to characterize the composition, structure, and morphology of ZrO2-TiO2 hollow spheres. The size of Au nanoparticles was found to be 3-5nm in diameter before being immobilized on the aforementioned mesoporous ZrO2-TiO2 layer and used as catalysts in the reduction of 4-nitrophenol to 4-aminophenol by NaBH4. Compared with TiO2/Au and ZrO2/Au, ZrO2-TiO2/Au NPs showed a higher catalytic activity because of due to mixed oxide synergistic effect. Besides, the sample gets the highest thermal stability and reactivity at 550°C, after calcining the hollow ZT/Au NPs at 550°C, 300°C and room temperature, respectively. Finally, a possible reaction mechanism was also proposed to explain the reduction of 4-nitrophenol to 4-aminophenol over ZrO2-TiO2/Au catalyst.

A novel hierarchical TiO 2 @Pt@mSiO 2 hollow nanocatalyst with enhanced thermal stability has been synthesized successfully. The formation procedure involves a facile synthesis of SiO 2 @TiO 2 @Pt nanospheres and a subsequent solvothermal process. During the hydrothermal process, original TiO 2 layer was transformed into a hierarchical nanostructure and, meanwhile, etch-released silica species redeposited on the surface of the in-situ grown TiO 2 nanoplatelets. In the catalytic system, the in-situ grown TiO 2 nanoplatelets were buried in the redeposited mSiO 2 layers and the Pt NPs dispersed uniformly between TiO 2 nanoplatelets and mSiO 2 layers. Importantly, the redeposited mSiO 2 layer provides a physical barrier to prevent Pt NPs from sintering up to 550 °C and the hierarchical TiO 2 nanostructure shows an obvious co-catalysis effect in the reduction of 4-NP. Besides, the mSiO 2 layer could also control the rapid crystallization process of TiO 2 nanoplatelets effectively. In the high temperature reaction of propane dehydrogenation, HHN exhibits a lower deactivation parameter, indicating the excellent thermal stability.

High-quality double-shelled TiO2 hollow spheres (DHS-Ti) assembled with TiO2 nanosheets have been synthesized for the first time through a simple hydrothermal treatment of sSiO2@TiO2 (TiO2-coated solid SiO2 spheres). The double-shelled structure shows a high BET surface area up to 417.6 m2 g−1. Anatase DHS-Ti of high crystallinity can be obtained without structural collapse by calcination treatment. The effects of cetyl trimethylammonium bromide (CTAB) concentration, pH, and hydrothermal reaction temperature have also been investigated with a series of contrast experiments. A formation mechanism involving the in situ growth of amorphous TiO2 nanosheets followed by the redeposition of dissolved silica species is proposed. Lastly, the DHS-Ti forming strategy can be extended as a general strategy to fabricate various morphological hollow nanostructures and double-shelled Pt nanocatalysts by rationally selecting functional sSiO2 nanoparticles as core materials. This work could open up a new strategy for controllable synthesis of complex hollow structures and other functional materials.

A novel strategy was described to construct Au-based yolk-shell SCVmS-Au nanocomposites (NCs), which combined the sol-gel template-assisted process for the assembly of hierarchical SCVmS NCs with modified CeO2/mSiO2 as yolks/shells, and the unique deposition-precipitation (DP) process mediated with Au(en)2Cl3 compounds for the synthesis of extremely stable supported Au nanoparticles (NPs). Characterization results indicated that the obtained SCVmS-Au NCs featured mesoporous silica shells, tunable interlayer voids, movable CeO2-modified cores and numerous sub-5nm Au NPs. Notably, the Au(en)2Cl3 was employed as gold precursors to chemically modify into the modulated yolk-shell structure through the DP process and the subsequent low-temperature hydrogen reduction induced the in-situ formation of abundant supported Au NPs, bestowing these metal NPs with ultrafine grain size and outstanding sinter-resistant properties that endured harsh thermal conditions up to 750°C. Benefiting from the structural advantages and enhanced synergy of CeO2-Au/mSiO2-Au yolks/shells, the SCVmS-Au was demonstrated as markedly efficient catalysts with superior activity and reusability in catalyzing the reduction of 4-nitrophenol to 4-aminophenol, and its pristine morphology still maintained after eight recycling tests.

In this work, a novel strategy has been proposed to synthesize a hierarchical Pt@TiO 2 -mSiO 2 yolk@shell nanocatalyst firstly. Inner active sites could be protected by the TiO 2 -mSiO 2 shell. The formation mechanism involves the in-situ growth of TiO 2 nanosheets and simultaneous redeposition of etch-released silica species. TEM images were employed to characterize each step of the synthesis process. During the hydrothermal process, original TiO 2 layer can be converted into a hierarchical structure and the inner SiO 2 sphere was etched out automatically. Furthermore, the reduction of 4-nitrophenol had been used to test the hierarchical Pt@TiO 2 -mSiO 2 yolk@shell nanocatalyst. The mixed oxides shell was constructed with in-situ grown hierarchical TiO 2 nanosheets and redeposited SiO 2 .

This work reports a novel type of sandwich-like hollow Au-based nanocatalyst, including a TiO2–ZrO2 shell, a hollow CeO2 core and Au nanoparticles of 2–5 nm. Uniform crystal ceria hollow nanostructures were synthesized using a simple one-step hydrothermal method without a template. Then binary TiO2–ZrO2 coated Au nanocatalysts were prepared via a facile bottom-up synthesis method. The structural features of the catalysts were characterized by several techniques, including SEM, TEM, EDX, FTIR, BET, XRD, UV-vis and XPS analyses. Using the reduction of 4-nitrophenol by NaBH4 as a model reaction, the TiO2–ZrO2/Au/CeO2 microspheres showed a superior catalytic activity and thermal stability compared with a pure TiO2 or ZrO2 layer. In addition, TiO2–ZrO2/Au/CeO2 microspheres calcined at 700 °C presented the highest thermal stability and reactivity. These comparative results were mainly attributed to the synergistic effect among the mixed oxide, hollow CeO2 core and Au NPs and the sandwich-like structure. As a consequence, this unique nanocatalyst will open a promising route for the fabrication of hollow binary-metal-oxide materials for future research and has great potential for other applications.

A Sn4+-doped double-shelled Pt/TiO2 hollow nanocatalyst (DHS-SnPt) with excellent photocatalytic H2 production efficiency was prepared successfully via a facile hydrothermal method. In the catalytic system, Pt active sites were in situ reduced by Sn2+ and showed an enhanced interaction with Sn species. The enhanced SnO2/Pt interface could accelerate the migration rate of e− from SnO2 to Pt, improving the charge separation efficiency of h+ and e−. The as prepared DHS-SnPt contained a very low Pt content (0.24 wt%) and showed the highest photocatalytic H2 production efficiency (ca. 18 496 μmol g−1 within 3 h), nearly 5.8 and 1.678 times as high as that of a pure double-shelled Pt/TiO2 hollow nanocatalyst and the traditional Sn4+ doped counterpart, respectively, demonstrating the significantly improved Pt atom utilization of DHS-SnPt in photocatalytic H2 evolution activity. On the basis of experimental results, a possible photocatalytic H2 production mechanism was proposed to explain the excellent H2 production efficiency of DHS-SnPt.

Herein, a novel combined strategy was developed for the preparation of double-shell hollow magnetic ultra-small Au-loaded ellipsoids (Fe@MO2–Au@H–SiO2) as powerful nanoreactors; these ellipsoids comprised double mesoporous shell structures, CeO2 or TiO2 inner active yolks, plenty of sub-3 nm Au nanoparticles (NPs), and magnetic Fe cores. The hierarchical yolk–shell architectures with ellipsoidal Fe2O3@MO2 (M: Ce or Ti)/mSiO2 as yolks/shells were fabricated first via a facile bottom-up assembly process based on sol–gel reactions. After this, encapsulation of numerous extremely stable Au NPs within the shell structures was accomplished via a two-stage reduction process based on the unique deposition–precipitation method mediated with Au(en)2Cl3 compounds; moreover, strong magnetism was integrated into the ellipsoids and inner voids were formed due to the transformation of Fe2O3 into smaller magnetic Fe. Note that ethylenediamine was used as a ligand to synthesize the stable gold precursors [Au(en)2]3+ that were chemically modified onto the double ellipsoidal shells under alkaline conditions. Due to their superior structural properties and enhanced composite synergy, the Fe@MO2–Au@H–SiO2 ellipsoids, especially Fe@CeO2–Au@SiO2, were shown as a highly efficient and recoverable nanocatalysts with outstanding activity and reusability in catalyzing the reduction of 4-nitrophenol to 4-aminophenol.

A novel strategy has been proposed to fabricate a hierarchical Ni–Al LDH platinum nanocatalyst (LDH-Pt). The formation mechanism involves loading of Pt NPs on nanocarbon spheres (NCSs) and calcination of NCSs/Pt/Al2O3 to remove inner NCSs. Then, Ni–Al LDH nanosheets in situ grew from hollow Pt/Al2O3 nanoclusters via a hydrothermal process, eventually fabricating the hierarchical LDH-Pt nanocatalyst. TEM and SEM images were employed to characterize each step of the synthesis process. During the hydrothermal process, most of the Pt NPs in Al2O3 shells were inlaid in the in situ grown LDH nanosheets, exhibiting a higher thermal stability than traditional impregnated LDH catalysts. Lastly, the as-synthesized LDH-Pt was tested with a high temperature reaction (590 °C) of propane dehydrogenation to further demonstrate the enhanced thermal stability of LDH-Pt.

The interfacial structural design of materials in nanoscale is a promising approach to regulate the physicochemical properties of materials and further optimize material properties for a variety of potential applications. Herein, PdNi-S/C nanowires with inductive sulfite has been successfully crafted through hydrothermal synthesis and applied as a superior hydrogen evolution reaction (HER) catalyst. Based on the autocatalytic mechanism, PdNi alloy nanoparticles were synthesized by controlling reduction kinetics with the presence of formic acid. Meanwhile, the sulfite is selected as an effective inductive agent to form PdNi-S/C nanowires with amorphous interfaces. The morphology, composition, and electronic structure of the synthesized PdNi-S/C were studied in detail. The PdNi-S/C manifests excellent HER performance in alkaline solution with an overpotentials of 67 mV at current density of 10 mA cm-2, a Tafel slope of 69.4 mV dec-1, and significantly long-term durability. The improvement of HER performance of the PdNi-S/C is attributed to the one-dimensional nanowire structure, abundant sulfur vacancies and defects, and the synergistic effect between PdNi-S nanowires with the graphite carbon. Furthermore, this present work offers a novel method for structure adjustment of materials to effectively control their property and catalytic performance.

A novel method has been developed for the preparation of highly active and thermally stable Au nanocatalysts, including a ZrO2-TiO2 (hereafter referred to as ZT) mixed oxide layer, a moveable Hollow Fe3O4 (hereafter referred to as HwFe3O4) magnetic core and some Au NPs of 5–8 nm. This method involves the in situ reduction of Au NPs on the C/HwFe3O4 nanospheres by using the C layer as the reducing agents. SEM, TEM, EDX, and XRD were employed to characterize the prepared samples. The results showed the ZT layer could increase the thermal stability and reactivity. The reduction of 4-nitrophenol (4-NP) into 4-aminophenol (4-AP) was employed as a model reaction to test catalytic performance in this work. The results showed the ZT/Au/C/HwFe3O4 nanospheres calcined at 750 °C showed the highest catalytic activity, compared to the samples calcined at 550 °C and RT, respectively. Meanwhile, the sample (750 °C) still has certain of magnetism, suggesting the desired samples could be separated by magnet. Finally, the catalyst was reused for several cycles to reduce the nitrophenol.

Well-dispersed hierarchical zeolite Y, structure-directed by ionic liquid 1-methyl-3-(3'-(trimethoxysilyl) propyl) imidazolium chloride, was synthesized for the first time using a novel ultrasonic/microwave synergistic synthe- sis (UMSS). The time required for the synthesis of zeolite Y by UMSS method was remarkably reduced to 6 h instead of 24 h under conventional hydrothermal conditions. The structures of all samples were characterized by XRD, BET, FT-IR, SEM and TEM. The results clearly demonstrated that the UMSS is a promising strategy to achieve zeolite Y with improved crystallinity, large BET surface area, bulky mesopore volume, well-dispersed morphology, small zeolite nanoparticle. The catalytic activity of hierarchically micro-mesoporous zeolite Y was evaluated by using the alkylation of o-xylene with styrene. Mesoporous zeolite Y synthesized by UMSS method showed significantly higher catalytic activity, stability and reusability, compared with conventional hydrothermal synthesis. It might be ascribed to its large mesoporous volume, small crystal nanoparticle and high surface area, minimizing the diffusion length as the reactant molecules diffuse into the pores, and correspondingly the products diffuse out of zeolites. This study suggests that UMSS method is a good alternative for the synthesis of micro-mesoporous zeolite Y, which may be of remarkable ben- efit for industrial applications.