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The development of high-efficiency and cost-effective difunctional electrocatalysts for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) are highly attractive to fulfill the practical water electrolysis. Herein, a novel low-cost difunctional cobalt-nickel sulfide (Co

Graphitic carbon nitride, regarded as a charming conjugated polymer, has been a visible light photocatalyst. Bulk carbon nitride endures the limited light absorption ability, few surface active sites and slow separation of photoinduced charge carriers, leading to the poor catalytic activity. Herein, a new carbon (C) and phosphorus (P) co-doped carbon nitride hollow tube with adjustable optical property (CPCN) was developed by applying melamine and polyacrylic amide as the precursors and phosphoric acid as the P source via a hydrothermal-thermal copolymerization way. The effects of polyacrylic amide content on the morphology and photocatalytic performance were intensively investigated. The special hollow tube favors the improvement of active sites and visible light harvesting ability. Meantime, C and P co-doping results in the narrow band gap and rapid charge transfer, thus enabling an enhanced catalytic activity under visible light irradiation. Particularly, CPCN-50 exhibits a remarkable H

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.

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.

The low specific surface area and low charge transfer efficiency of conventional graphite carbon nitride (g-C

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.

Carbon doped honeycomb-like graphitic carbon nitride (g-C3N4) was prepared by one-step thermal polymerization, which derived from chitosan as a carbon source together with the melamine-cyanuric acid complex as a supramolecular precursor. Interestingly, the carbon doped g-C3N4 displayed an increased specific surface area and a more negative conduction band energy level, which not only provided a large number of reaction sites for the photocatalytic hydrogen production, but also effectively enhances the separation of photogenerated electrons-holes. And the experimental results showed that the hydrogen evolution rate of the optimal sample was as high as 320 μmol·h−1, which is 29.10 times than that of bulk g-C3N4 (11 μmol·h−1). More importantly, this work may provide a promising idea for the design of efficient g-C3N4 by controlling the material morphology and combining the electronic modulation strategy.

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 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.

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/ZnFe

Carbon nitride, as an outstanding photocatalyst for hydrogen production, displays a limited photocatalytic performance on account of the insufficient light absorption and low surface area. Herein, three-dimensional mesoporous carbon nitride with large surface area was prepared by using freeze-dried cyanuric acid-melamine supramolecular aggregates and ionic liquid as precursor and template, respectively. The results find that as-prepared carbon nitride materials possess the 3D interconnected open-framework with porous channels owing to the decomposition of ionic liquid and precursor under high temperature calcination, which in favor of the contact between active sites and reactants as well as the improvement of charge carrier transport rate. Compared to the pure carbon nitride, the obtained CNF-0.005 was endowed with the ultrathin nanosheets, broaden light adsorption, high separation rate of photogenerated carriers and improved photocatalytic activity. Especially, the above-mentioned sample exhibits a superior visible light driven photocatalytic H2 production capability and excellent durability, as high as 129.5 μmol/h, which is about 27.6 times and 1.8 times than that of the bulk CN and pure CNF, respectively. This work opens up an ingenious strategy towards the fabrication of high-performance carbon nitride with controllable structure and improved surface area for efficient hydrogen production.

The two dimensional (2D) lamellar structure materials with micron length of lateral can offer abundant reactive sites, high surface area and high flexibility for separating the photo-induced electron-hole pairs, and the obtained nanosheets possess tremendous potential to achieve efficient photocatalytic performance. Herein, we design and successfully synthesize 2D MOF-derived leaf-like structured Co

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 CeO