Renxi Jin

In situ loading of Ag2WO4 on ultrathin g-C3N4 nanosheets with highly enhanced photocatalytic performance.

The g-C3N4 nanosheets (g-C3N4NS) exhibit more excellent property than common bulk g-C3N4 (g-C3N4-B) due to their large surface areas, improved electron transport ability and well dispersion in water. In this work, ultrathin g-C3N4NS with a thickness of about 2.7nm have been synthesized by a simple thermal exfoliation of bulk g-C3N4, and then Ag2WO4 nanoparticles are in situ loaded on their surface to construct the Ag2WO4/g-C3N4NS heterostructured photocatalysts. Due to their unique physicochemical properties, the as-prepared heterostructures possess a fast interfacial charge transfer and increased lifetime of photo-excited charge carriers, and exhibit much higher photocatalytic activity. Under visible light irradiation, the optimum photocatalytic activity of Ag2WO4/g-C3N4NS composites is almost 53.6 and 26.5 times higher than that of pure g-C3N4-B and Ag2WO4/g-C3N4-B heterostructures towards the degradation of rhodamine B, respectively, and is almost 30.6 and 9.8 times higher towards the degradation of methyl orange, respectively. In addition, the natural sunlight photocatalytic activities of the as-prepared samples are also investigated.

In situ assembly of monodispersed Ag nanoparticles in the channels of ordered mesopolymers as a highly active and reusable hydrogenation catalyst

In this study, we report a simple in situ auto-reduction strategy for the fabrication of Ag@FDU-15 nanocomposites, in which the small sized Ag nanoparticles are monodispersed in the channels of FDU-15 ordered mesopolymers. The as-prepared Ag@FDU-15 nanocomposites were characterized by small and wide angle X-ray diffraction (XRD), nitrogen sorption, thermo-gravimetric analysis (TGA), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). TEM results show that the silver nanoparticles are uniformly dispersed with a mean diameter of 5.6 ± 0.5 nm. When used as a hydrogenation catalyst, the Ag@FDU-15 nanocomposites exhibit excellent catalytic performance and reusability for the reduction of 4-nitrophenol (4-NP) in the presence of NaBH4.

Sandwich-structured graphene-nickel silicate-nickel ternary composites as superior anode materials for lithium-ion batteries.

We report the synthesis of sandwich-structured graphene-nickel silicate-Ni ternary composites by using the solvothermal method followed by a simple in situ reduction procedure. The composites show an interesting structure with graphene sandwiched between two layers of well-dispersed Ni nanoparticles (NPs) anchored on ultrathin nickel silicate nanosheets. These ternary composites exhibit enhanced performance as anode materials owing to the synergistic effect between the graphene matrix and electrochemically inert Ni nanoparticles, an effect that holds promise for the design and fabrication of other advanced electrode materials.

Facile synthesis of well-dispersed silver nanoparticles on hierarchical flower-like Ni3Si2O5(OH)4 with a high catalytic activity towards 4-nitrophenol reduction.

Layered nickel silicate nanoflowers (NSFs) with a hierarchical nanostructure have been successfully fabricated by a template-free solvothermal method. The as-prepared nanoflowers were composed of many interconnected edge-curving lamellae with a thickness of about 15 nm and had a high specific surface area (279 m(2)  g(-1)) and large pore volume (0.67 cm(3)  g(-1)). The highly dispersed small silver nanoparticles (AgNPs) were immobilized on the surface of NSFs through the in situ reduction of Ag(+) by Sn(2+). The AgNP/NSF nanocomposites showed a high performance in the catalytic reduction of 4-nitrophenol. In particular, there was no visible decrease in the catalytic activity of the reused catalysts even after being recycled four times. The as-prepared AgNP/NSF nanocomposites might be an excellent catalyst owing to their availability, formability, chemical and thermal stability, and high specific surface area.

A General Route to Hollow Mesoporous Rare‐Earth Silicate Nanospheres as a Catalyst Support

Hollow mesoporous structures have recently aroused intense research interest owing to their unique structural features. Herein, an effective and precisely controlled synthesis of hollow rare-earth silicate spheres with mesoporous shells is reported for the first time, produced by a simple hydrothermal method, using silica spheres as the silica precursors. The as-prepared hollow rare-earth silicate spheres have large specific surface area, high pore volume, and controllable structure parameters. The results demonstrate that the selection of the chelating reagent plays critical roles in forming the hollow mesoporous structures. In addition, a simple and low-energy-consuming approach to synthesize highly stable and dispersive gold nanoparticle-yttrium silicate (AuNPs/YSiO) hollow nanocomposites has also been developed. The reduction of 4-nitrophenol with AuNPs/YSiO hollow nanocomposites as the catalyst has clearly demonstrated that the hollow rare-earth silicate spheres are good carriers for Au nanoparticles. This strategy can be extended as a general approach to prepare multifunctional yolk-shell structures with diverse compositions and morphologies simply by replacing silica spheres with silica-coated nanocomposites.

Facile Fabrication of Well-Dispersed Pt Nanoparticles in Mesoporous Silica with Large Open Spaces and Their Catalytic Applications.

In this paper, a facile strategy is reported for the preparation of well-dispersed Pt nanoparticles in ordered mesoporous silica (Pt@OMS) by using a hybrid mesoporous phenolic resin-silica nanocomposite as the parent material. The phenolic resin polymer is proposed herein to be the key in preventing the aggregation of Pt nanoparticles during their formation process and making contributions both to enhance the surface area and enlarge the pore size of the support. The Pt@OMS proves to be a highly active and stable catalyst for both gas-phase oxidation of CO and liquid-phase hydrogenation of 4-nitrophenol. This work might open new avenues for the preparation of noble metal nanoparticles in mesoporous silica with unique structures for catalytic applications.

In situ reduction of well-dispersed nickel nanoparticles on hierarchical nickel silicate hollow nanofibers as a highly efficient transition metal catalyst

Despite being a promising substitute for noble metals used in nanocatalysts, the inexpensive and earth-abundant transition-metal catalysts are still impractical, mainly due to their low catalytic activity and durability. Therefore, acquiring a highly active and stable transition metal catalyst is urgently desirable. In this paper, we describe a mild method for the synthesis of small-sized nickel nanoparticles (NiNPs) immobilized on hierarchical double-shell nickel silicate hollow nanofibers (NSHNFs) in a large scale. The NiNPs/NSHNFs catalysts show high catalytic activities and excellent stabilities towards the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP). The reduction has a pseudo-first-order rate constant of 13.21 × 10−3 s−1 and an activity parameter of 13.21 × 10−3 s−1 mg−1, which are higher than those of the previously reported Ni-based catalysts. In particular, the NiNPs/NSHNFs catalysts can be easily separated from the solution by gravitational sedimentation owing to their unique structure. Therefore, our NiNPs/NSHNFs nanocomposites hold promise for further industrial applications as cheap and effective catalysts.