Jiu-Ju Feng

Controlled fabrication of well-dispersed AgPd nanoclusters supported on reduced graphene oxide with highly enhanced catalytic properties towards 4-nitrophenol reduction

To realize the efficient and complete removal of organic pollutants in waste water, it is highly urgent for scalable synthesis of either self-supported bimetallic nanocatalysts or anchored on carbon-based materials. In this study, a simple one-pot coreduction method was developed for preparing well-dispersed AgPd alloyed nanoclusters uniformly dispersed on reduced graphene oxide (AgPd NCs/rGO) at room temperature by utilizing 5-azacytosine as the capping agent. The nanocomposites were characterized by a set of physical characterizations. The formation mechanism and catalytic mechanism were discussed in some details. Moreover, the prepared AgPd NCs/rGO exhibited dramatically increased catalytic properties towards the reduction of 4-nitrophenol (4-NP) in the presence of NaBH4 when compared to commercial Pd/C (20u202fwt.%).

One-pot aqueous fabrication of reduced graphene oxide supported porous PtAg alloy nanoflowers to greatly boost catalytic performances for oxygen reduction and hydrogen evolution

Herein, reduced graphene oxide supported porous PtAg alloy nanoflowers (PtAg NFs/rGO) were synthesized by a simple one-pot aqueous method using pyridinium-based dicationic ionic liquid (1,4-bis(pyridinium)butane dibromide, Bpb-2Br) as the new structure-director and stabilizing agent. The products were characterized by a series of techniques. The obtained nanocomposite had more positive onset potential (1.03u202fV) for oxygen reduction reaction (ORR) in alkaline electrolyte than those of commercial Pt/C (50u202fwt%, 0.96u202fV) and home-made Pt nanoparticles (NPs)/rGO (Pt NPs/rGO, 0.97u202fV), showing the enhanced catalytic performance for hydrogen evolution reaction (HER) with the positive onset potential (-26u202fmV) and a small Tafel slope (31u202fmV dec-1) relative to Pt/C (-18u202fmV, 31u202fmV dec-1) and Pt NPs/rGO (-42u202fmV, 36u202fmV dec-1) in 0.5u202fM H2SO4.

Dentritic platinum-palladium/palladium core-shell nanocrystals/reduced graphene oxide: One-pot synthesis and excellent electrocatalytic performances

Herein, we developed a facile one-pot co-reduction method to fabricate highly dentritic platinum-palladium/palladium core-shell nanocrystals on reduced graphene oxide (PtPd@Pd NCs/rGO), where poly-l-lysine (PLL) worked as the eco-friendly structure director and stabilizer. The nanocomposite was mainly characterized by microscopic analysis, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and thermogravimetric analysis (TGA), along with the discussion of the formation mechanism. The synthesized PtPd@Pd NCs/rGO have the enlarged electrochemically active surface area (ECSA) of 51.65u202fm2u202fg-1, showing 1.3 folds enhancement in the peak current density relative to commercial Pt/C (50u202fwt%) for glycerol oxidation reaction (GOR), coupled with the small Tafel slope of 28u202fmVu202fdec-1 for hydrogen evolution reaction (HER).

Poly-L-lysine mediated synthesis of palladium nanochain networks and nanodendrites as highly efficient electrocatalysts for formic acid oxidation and hydrogen evolution

The morphology- and size-tunable synthesis of nanocatalysts has attracted substantial research interest especially in catalysis. In this work, we synthesized free-standing Pd nanochain networks (Pd NCNs) and Pd nanodendrites (Pd NDs) through a direct poly-l-lysine (PLL)-mediated one-pot aqueous method. The presence of PLL and its concentrations were critical in this regard, showing PLL as the structure-directing and capping agents during the nucleation and crystal growth procedures. The synthesized architectures exhibited improved catalytic activity and enhanced durability towards formic acid oxidation and hydrogen evolution reactions relative to commercial Pd black catalyst. Moreover, the electrochemical active surface area and the electrocatalytic performance of Pd NCNs were dramatically enhanced in comparison to Pd NDs mainly owing to the unique network-like structure of Pd NCNs.

Platinum 69 -cobalt 31 alloyed nanosheet nanoassemblies as advanced bifunctional electrocatalysts for boosting ethylene glycol oxidation and oxygen reduction

Pt-based bimetallic nanocrystals are feasible to dramatically improve the catalytic performances in fuel cells via morphology- and composition-engineering. Herein, bimetallic platinum69-cobalt31 nanosheet nanoassemblies (Pt69Co31 NSNSs) were facilely synthesized through a one-pot co-reduction solvothermal strategy in oleylamine (OAm), using cetyltrimethylammonium chloride (CTAC) and allantoin as the directing agents. The current synthesis highly depended on the critical concentrations of Pt and Co precursors, the combined use of allantoin to OAm as the co-reductant, and the use of proper allantoin concentration. The obtained nanocatalyst exhibited largely enhanced electrocatalytic activity and durable ability towards ethylene glycol oxidation reaction (EGOR) and oxygen reduction reaction (ORR) relative to home-made Pt85Co15 nanoparticles (NPs), Pt19Co81 NPs and Pt black catalysts due to its much larger electrochemically active surface area than the contrasts.

Highly sensitive label-free amperometric immunoassay of prostate specific antigen using hollow dendritic AuPtAg alloyed nanocrystals

Herein, well-defined hollow dendritic AuPtAg alloyed nanocrystals (ANCs) were synthesized by a simple L-proline-mediated one-pot aqueous method. More importantly, the synthesized hollow dendritic architectures provide a suitable platform for immobilization of anti-prostate specific antigen (PSA). The resultant label-free immunosensor exhibited the improved performance for highly sensitive detection of PSA based on the enhanced catalytic currents of K3[Fe(CN)6] as a signal probe. Impressively, the immunosensor showed the wide linear range of 0.05-50u202fngu202fmL-1 and low detection limit of 0.017u202fngu202fmL-1 under optimal conditions for the assay of PSA, couple with the improved stability, reproducibility and selectivity. It provides a promising platform for clinical research and diagnosis.

Melamine-assisted solvothermal synthesis of PtNi nanodentrites as highly efficient and durable electrocatalyst for hydrogen evolution reaction

Rational design of highly efficient and durable electrocatalysts for hydrogen evolution reaction (HER) is of prime importance for renewable and sustainable energy. Herein, PtNi nanodentrites (PtNi NDs) were facilely synthesized in oleylamine (OAm) by a one-pot solvothermal method, using melamine and cetyltrimethylammonium chloride (CTAC) as co-structure-directing agents. The obtained catalyst showed superior catalytic activity and enhanced durability for HER relative to commercial Pt/C, home-made PtNi3 nanocrystals (NCs) and Pt3Ni NCs both in alkaline and acidic media. The enhanced HER activities are attributed to bimetallic synergies and interface structures in PtNi NDs. This work provides an effective strategy to prepare highly efficient and durable electrocatalysts for HER.

Facile solvothermal fabrication of Pt 47 Ni 53 nanopolyhedrons for greatly boosting electrocatalytic performances for oxygen reduction and hydrogen evolution

Pt-based bimetallic nanostructures with low content of Pt were considered as one of the attractive nanocatalysts for their high Pt utilization efficiency, remarkable catalytic characters and cost-effectiveness in facilitating the sluggish cathodic reactions in fuel cells. Herein, three-dimensional Pt47Ni53 nanopolyhedrons (NPHs) with abundant active sites were constructed by a facile one-pot solvothermal strategy, in which cytosine and cetyltrimethylammonium chloride (CTAC) worked as the co-structure directing agents. The Pt47Ni53 NPHs were mainly characterized by a series of techniques, showing the high catalytic activity and stability towards oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER) in comparison to Pt13Ni87 nanocrystals (NCs), Pt63Ni37 NCs, commercial Pt black and/or Pt/C catalysts. Impressively, the mass activity of Pt47Ni53 NPHs was about 215.80u202fmA mgPt-1 for ORR, approximately 4-time increase relative to Pt black (49.60u202fmA mgPt-1). These results demonstrate the promising applications of the synthesized nanocatalysts in energy storage and transformation.

Hollow Ag44Pt56 nanotube bundles with high electrocatalytic performances for hydrogen evolution and ethylene glycol oxidation reactions

It is a main challenge to synthesize highly efficient and durable nanocatalysts towards hydrogen evolution reaction (HER) and alcohol oxidation reaction in energy conversion and storage. Herein, a green wet-chemical approach was developed to directly prepare hollow Ag44Pt56 nanotube bundles (H-Ag44Pt56 NTBs), utilizing 5-azacytosine as a structure-directing agent. The obtained electrocatalyst displayed superior catalytic activity and durability for HER in acid media, and the great improvement in catalytic performance for ethylene glycol oxidation reaction (EGOR) in the alkaline electrolyte, outperforming home-made Ag34Pt66 nanoparticles (NPs), Ag70Pt30 NPs, and commercial Pt/C catalysts. The high electrocatalytic characters are mainly attributed to the special nanostructures and the synergetic effects between the bimetals.

Facile synthesis of prickly platinum-palladium core-shell nanocrystals and their boosted electrocatalytic activity towards polyhydric alcohols oxidation and hydrogen evolution

Herein, prickly platinum-palladium core-shell nanocrystals (Pt@Pd NCs) were prepared by a facile one-pot aqueous method, only taking sodium pyrrolidone carboxylate (PCA-Na) as the structure director and stabilizing agent. The products were mainly characterized by microscopic analysis, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), followed by discussing the formation mechanism in details. The electrochemical characterizations were examined by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and chronoamperometry (CA). The results revealed that the prepared architectures had the biggest current density (58.4u202fmAu202fcm-2) for ethylene glycol oxidation, which is 3.5-fold, 1.2-fold, 2.3-fold and 2.4-flod enhancement relative to those of home-made single Pt nanoparticles (NPs) and Pd NPs, commercial Pt black and Pd black catalysts, respectively. Also, the obtained Pt@Pd NCs showed improved catalytic activity and stability towards glycerol oxidation and hydrogen evolution reactions compared to the references.