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The PdAu bimetallic nanocrystals supported on Fe 3 O 4 magnetic nanoparticles (PdAu/Fe 3 O 4) were synthesized by a facile incipient wetness impregnation method. The as-synthesized bimetallic catalyst PdAu/Fe 3 O 4 exhibits significantly enhanced catalytic properties for Heck cross-coupling reaction under aerobic condition compared to the monometallic counterparts. The enhanced catalytic activity is attributed to the low-alloyed structure with a Pd-rich shell and an Au-rich core as well as the synergistic effect between Pd and Au according to X-ray photoelectron spectroscopy (XPS) results. Also, the cycle performance of the magnetic catalyst was evaluated. Reasonable yield was achieved after 6 cycles. In addition, the catalytic behavior of PdAu/Fe 3 O 4 for Suzuki reaction was investigated, providing excellent yield and moderate cycle performance. These results suggest the magnetic bimetallic catalyst PdAu/Fe 3 O 4 is a promising catalyst for Heck and Suzuki cross-coupling reactions. [ABSTRACT FROM AUTHOR]

Graphical abstract Abstract Electrochemical property and detection performance of nanocatalysts are largely affected by the component and morphology. Here, an advanced class of PtCu nanocrystal with uniform trifurcate structure has been synthesized by using KI as the structure-directing agent during the reduction process. Due to the large surface area of such synthesized dendritic trifurcate nanocrystal and the synergistic effect between Pt and Cu, this nanocatalyst performed nicely when applied it to the electrochemical detection of caffeic acid. Specifically, the detection limit is 0.35 μM (S/N = 3) and the linear range is wide from 1.2 μM-1.9 mM. The finding may be beneficial for developing novel and high-performance sensors for the monitoring of dietetical and environmental safety. [ABSTRACT FROM AUTHOR]

The design of high-performance electrocatalysts for the electrooxidation of liquid fuel is highly desirable for the commercial development of fuel cells. Engineering the nanocatalysts with high surface active areas has been regarded as one of the most efficient approach to obtain the high-performance electrocatalysts. For this reason, we herein demonstrated a facile ultrasonic-assisted synthetic method to successfully fabricate the trimetallic PtAuRu nanostructures with highly porous features and perpendicular pore channels. By virtue of the highly porous properties and abundant pore channels, the resulted PtAuRu nanocrystals (PtAuRu NCs) with the optimized atomic ratio exhibit extremely high electrocatalytic performances toward formic acid oxidation with the mass and specific activities of 1044.1 mA mg −1 and 14.5 mA cm −2 , 4.1 and 2.2 times higher than those of commercial Pt/C, respectively. Our tremendous efforts in this work can not only provide a facile strategy for the preparation of excellent electrocatalysts but also greatly accelerate the commercial development of fuel cells and beyond. [ABSTRACT FROM AUTHOR]

This work reports a simple method to design and synthesize PdNi nanospheres which supported on Vulcan XC-72R Carbon with NaBH 4 as reducing agent at ambient temperature and their superior electrocatalytic activity. The results of electrochemical measurements indicate that the PdNi nanospheres exhibit improved catalytic activity, excellent durability as well as higher long-term stability towards methanol oxidation reaction in comparison with commercial Pd/C catalysts. Furthermore, it is interpreted that the enhanced catalytic performance of the PdNi nanospheres is owing to the electronic effect between Pd and Ni and the spherical shape structure with rough surface. These findings highlighted the significance of precisely synthesizing the Pd/Ni nanospheres supported on Vulcan XC-72R Carbon and their emerging applications as electrocatalysts for direct methanol fuel cells. [ABSTRACT FROM AUTHOR]

Solvents play a key role in controlling the fabrication and modification of nanoparticles. We herein demonstrated that the dispersibility, stability, morphology and structure of PdAu nanoparticles varied with the polarity, special functional groups and self-properties of solvents. The underlying causes for solvent dependence were attributed to the interactions between the solvent and PdAu nanoparticles coated with PVP. Additionally, in comparison with commercial Pd/C, the obtained PdAu nanowire networks prepared in different solvents exerted considerable high electrocatalytic activity and stability towards ethylene glycol and isopropanol electrooxidation, particular for the PdAu nanowire networks prepared in DMF, which exhibited the well-dispersed nanowire network structure with large quantity of surface active areas, superior electrocatalytic activity together with long-term stability. Our efforts not only highlighted the facile preparations of the effective PdAu nanowire networks for the potential anodic catalysts for the application of fuel cells, but also facilitated the selections of appropriate solvents for preparing valid catalysts. [ABSTRACT FROM AUTHOR]

In this work, PdPbPt interconnected network type nanoparticles have been fabricated by a facile route, and the as-prepared PdPbPt composites were characterized by transmission electron microscopy (TEM), high-resolution TEM (HRTEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS) and electrochemical measurements. It is found that PVP plays an important role in enhancing the dispersion and stability of the catalyst. Moreover, the resultant network Pd 1 Pb 1 Pt 0.027 nanoparticles reveal superior electrocatalytic activity and stability for the ethanol electro-oxidation reaction for comparison with other as-synthesized catalysts, which the anodic peak current density on Pd 1 Pb 1 Pt 0.027 electrode can reach as high as 6936 mA mg −1 , suggesting that Pd 1 Pb 1 Pt 0.027 composite can be a promising catalyst for fuel cells. [ABSTRACT FROM AUTHOR]

This paper reports a facile electrochemical approach for synthesizing the Pd nano-leaves supported on reduced graphene oxide (RGO) modified glassy carbon electrode (GCE). The as-synthesized Pd nano-leaves/RGO/GCE catalyst has been characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). SEM images show that a large number of Pd nano-leaves are uniformly deposited on the surface of RGO. Electrochemical measurements indicate that the as-synthesized Pd nano-leaves/RGO/GCE catalyst displays higher electrocatalytic activity and stronger poisoning-tolerance towards formic acid oxidation reaction as compared to the Pd nano-leaves/GCE and commercial Pd/C/GCE catalysts. This work explores a novel approach for the formation of nano-leaves structure, which can provide its important application in fuel cells. [ABSTRACT FROM AUTHOR]

A promising electrochemical sensor, Pt nanoparticles decorated on the surface of reduced graphene oxide (RGO) sheets were facilely synthesized by a one-pot hydrothermal method. The morphology and composition of as-prepared Pt–RGO composites have been characterized by transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy and X-ray diffraction (XRD). It is found that Pt nanoparticles with ca. 4.81 ± 1.54 nm in diameter were evenly distributed on the surface of RGO sheets. The cyclic voltammetry shows that Pt–RGO nanocomposite has a higher electron transfer rate and remarkable increase electrochemical activity toward the oxidation of nitrite. The amperometry reveals that the Pt–RGO modified electrode exists a good linear relationship between peak current and concentration of nitrite with a low detection limit of 0.1 μM and high sensitivity of 496.4 μA mM −1 . Moreover, the as-synthesized Pt–RGO electrode display a fast amperometric response within 4 s. Compared to the bare Pt nanoparticles or the RGO modified glassy carbon (GC) electrode, the as-synthesized Pt–RGO nanocomposite shows a well reproducibility, stability and anti-interference electrocatalytic performance toward nitrite sensing. [ABSTRACT FROM AUTHOR]

Efficient photocatalytic degradation of organic pollutants in water heavily depends on the elaborate design of the micro/chemical structure of the catalyst. For g-C 3 N 4 , the synergistic incorporation of heterojunction structures is an effective strategy toward enhanced charge separation and broadened response range of light irradiation, rendering improved performances in photocatalysis. Herein, we propose a WO 3 /BiOCl heterojunction (WB) supported on graphite phase g-C 3 N 4 (CN) nanosheets that simultaneously enables local surface plasmon resonance (LSPR) effect (by WO 3) and promotes charge separation at the catalyst interface (by BiOCl). The WO 3 /BiOCl/g-C 3 N 4 nanocomposites (WB-CN) show high efficiency in the photo-degradation of two model antibiotics, levofloxacin (OFLX) and tetracycline hydrochloride (TC), which are 2.57 and 2.05 times higher than that of unmodified CN, respectively. The Free radical capture experiments confirmed that the significant reactive species are the photo-generated holes and superoxide radicals. Photoluminescence and photoelectrochemical characterizations suggest an LSPR-coupled charge separation mechanism behind the enhanced photocatalytic activity of WB-CN, creating a local Z-scheme heterojunction structure in the composites that improves the separation efficiency of photo-generated carriers. Together, our results highlight the great potential of composite design in developing CN-based photocatalysts for environmental technology. g-C 3 N 4 -supported WO 3 /BiOCl heterojunctions were successfully prepared to achieve highly efficient degradation of antibiotics near infrared [Display omitted] • WB-CN nanocomposites present broader response region compared to CN under simulated sunlight irradiation. • WB-CN nanocomposites show superior photocatalytic activity for degrading antibiotics and mineralization for TC. • WO 3 with LSPR effect and BiOCl as electron-transfer mediators synergistically promote the charge transfer. • Possible degradation pathway of OFLX and TC oxidation was elucidated. [ABSTRACT FROM AUTHOR]

A facile electrochemical approach to synthesize reduced graphene oxide (RGO) modified glassy carbon (GC) electrode as an excellent support for anchoring PtCuAu nanoparticles is reported. The as-prepared PtCuAu/RGO catalyst has been characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and electrochemical methods. It is found that the PtCuAu nanoparticles formed alloy structures and are evenly distributed on the RGO substrate. Compared with Pt/RGO, PtCu/RGO, PtAu/RGO and CuAu/RGO electrodes, the PtCuAu/RGO catalyst exhibits distinctly enhanced current density and nice stability toward formic acid electrooxidation. The experimental results indicate that the prepared PtCuAu/RGO catalyst has enormous potential applications in direct formic acid fuel cells (DFAFC). [ABSTRACT FROM AUTHOR]

Highlights: [•] The f-RGO/GCE was fabricated by electrochemical method. [•] The flower-like graphene framework has a well-defined distributed on GCE. [•] The f-RGO/GCE shows good responsiveness and high selectivity for DA detection. [ABSTRACT FROM AUTHOR]

Highlights: [•] The Pt–RuNPs/RGO/CCE was fabricated by electrochemical method. [•] Pt–Ru nanoparticles deposited on RGO appear to be well-dispersed. [•] The Pt–RuNPs/RGO/CCE shows high catalytic activity for methanol electrooxidation. [ABSTRACT FROM AUTHOR]

Abstract: A facile and cost effective approach has been developed towards electrochemical fabrication of graphene-modified carbon fiber electrode (GE/CFE) to determine the content of uric acid (UA) via cyclic voltammetry (CV) and potentiostatic (i–t) methods. The combined merits of GE and CFE endow the electrode with large specific surface area and high electrical conductivity. The advantage of thus obtained GE/CFE for UA detection is supported by its higher peak current intensity and lower oxidation potential compared with those of bare glassy carbon electrode (GCE), bare carbon fiber electrode (CFE), and graphene-modified glassy carbon electrode (GE/GCE). Further amperometric study gives a wide liner range from 0.194μM to 49.68μM and a low detection limit of 0.132 μM (S/N =3) with fast response time for the determination of UA on GE/CFE. The determination of UA with GE/CFE is highly selective and reproducible, within a relative standard deviation of 2.8%. [Copyright &y& Elsevier]

Pyramidal Pt-FeNi@C, P hybrid catalyst with ultralow Pt doping (only 0.4 atom%) are designed by a partially phosphating of metal-organic frameworks strategy, which exhibits dramatically enhanced HER catalytic performance both in acidic and alkaline media. It remains an immense challenge to design robust electrocatalysts for HER both in acidic and alkaline electrolytes. Herein, we report a partially phosphating of metal-organic frameworks strategy to prepare a hybrid catalyst of FeNi alloy/FeNi phosphide with ultralow doped Pt (only 0.4 atom%). With effectively modulated electronic configurations and unique tunneling effects, the optimal Pt-FeNi@C, P exhibits prominent HER activities with the overpotential of 53 and 52 mV (@10 mA cm−2) in acidic and alkaline media, respectively, as well as superior stability. Noticeably, Pt-FeNi@C, P shows significantly enhanced mass activities (@−0.05 V vs RHE) both in acid and alkaline electrolytes, which are 6.6 and 5.6 times higher than that of commercial Pt/C. Based on high electronegativity of P atoms, the negatively charged phosphorus atoms and positively charged metal atoms work in a cooperative manner as the proton-acceptor and hydride-acceptor centers, respectively, substantially supporting the outstanding catalytic activity of Pt-FeNi@C, P. [ABSTRACT FROM AUTHOR]

Electrocatalyzing ethanol oxidation to convert chemical energy into electrical energy is significant for alleviating the energy crisis and environmental pollution but still challenging because of the lack of highly efficient and low-cost catalysts. Herein, we report the design and fabrication of an advanced nanocatalyst constructed by uniformly distributing 3D palladium nanoflowers (NFs) on the surface of nitrogen-doped graphene (NG). Impressively, taking advantages of the morphological and structural advantages, the as-obtained Pd NFs/NG with high surface area can display greatly improved electrocatalytic activity for ethanol oxidation reaction (EOR) in alkaline media. More importantly, the introduction of NG support renders this composite high conductivity and fast electron transport, resulting in a large promotion in electrocatalytic activity and stability. This work provides facile synthetic concept to build multi-dimensional composite catalysts with synergetic enhancement effects for wide electrocatalytic reactions. [ABSTRACT FROM AUTHOR]

Design of high performance and low cost electrocatalysts for the oxidation of small organic molecules remains a great challenge for the practical application of direct fuel cells. Herein, a novel composite catalyst composed of PdAu nanoparticles (NPs) uniformly dispersed on the polydopamine functionalized MWCNTs (PDA-MWCNTs) has been synthesized. TEM images indicate that MWCNTs are successfully coated by PDA, and the as-prepared PdAu NPs are homogeneously dispersed on the PDA functional MWCNTs with smaller sizes than those on pristine MWCNTs. Electrochemical tests reveal that PDA-MWCNTs is a promising catalyst carrier for direct ethylene glycol fuel cell (DEGFC), and the PdAu(1:1)/PDA-MWCNTs catalyst displays the highest peak current density among all catalysts towards ethylene glycol oxidation reaction (EGOR) in alkaline medium, with mass activity of 1540.3 mA mg Pd −1, which is 1.5, 2.6, 9.8, 13.4 and 2.0 times greater than those of PdAu(1:3)/PDA-MWCNTs, PdAu(3:1)/PDA-MWCNTs, Pd/PDA-MWCNTs, Pd/MWCNTs and commercial Pd/C catalysts, respectively. In addition, PdAu(1:1)/PDA-MWCNTs catalyst also exhibits the best stability. These findings are valuable for the development of advanced Pd-based catalysts, which will help promote the industrialization of direct fuel cell. [ABSTRACT FROM AUTHOR]