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Pt is the ideal anode catalyst in fuel cells. In this paper, in order to increase the utilization of Pt, the PtAu nanowire networks (NWNs) with ultralow content of Pt are fabricated by a simple silicon monoxide (SiO) reduction method without any capping agent. PtAu NWNs supported on carbon black with Pt content of 1 wt% (Pt 0. 05 Au NWNs) are employed as catalysts for formic acid oxidation (FAO) and methanol oxidation reaction (MOR), whose mass activities are as high as 4998.9 and 2282.3 mA∙mg Pt −1, respectively. The network structure facilitates the electron transfer and increases the stability of the catalysts. The PtAu composite experiences compressive lattice strain as confirmed by X-ray powder diffraction (XRD). The Pt 0. 05 Au NWNs catalyst with low Pt content results in the largest strain variation compared with PtAu composited of other ratios, which may downshift the d-band center of Pt and lead to the higher electrocatalytic activity in oxidation reaction. • PtAu nanowire networks are fabricated by a simple Si–H bond reduction method. • The network structure facilitates the electron transfer and increases the stability. • Pt 0. 05 Au/C with Pt content of 1 wt% shows high mass activities to FAO and MOR. • The lattice strain of PtAu is formed during the fabrication process. [ABSTRACT FROM AUTHOR]

Extremely low content of Ruthenium (Ru) nanoparticles were loaded on the carbon black (Ru/C) via reducing Ru ions with silicon monoxide. The obtained Ru/C nanocomposites exhibit an exciting electrochemical catalytic activity for hydrogen evolution reaction (HER) in the oxygen-free 0.5 M H 2 SO 4 medium. The optical one (Ru/C-2) with a low Ru amount of 2.34% shows higher activity than previously reported Ru-based catalysts. The overpotential at 10 mA cm−2 is 114 mV and the Tafel slope is 67 mV·dec−1. Ru/C-2 catalyst also has good stability. The overpotential that afford the current density of 10 mA cm−2 of 20 wt% Pt/C increased 92 mV while that of Ru/C-2 only increased 50 mV after a 30,000 s chronopotentiometry test. Furthermore, the mass activity of Ru/C-2 catalyst is even better than that of the commercial 20 wt% Pt/C when the overpotential is larger than 0.18 V. This silicon monoxide-mediated strategy may open a new way for the fabrication of high performance electrocatalysts. Extremely low content of Ruthenium nanoparticles are loaded on carbon black (Ru/C) via reducing Ru ions with silicon monoxide. The obtained Ru/C nanocomposites exhibit an exciting electrochemical catalytic activity for hydrogen evolution reaction with low onset overpotential and Tafel slope, high mass activity and good stability. Image 1 • Ru nanoparticles are loaded on carbon black via reducing Ru3+ with Si H bonds. • Ru/C-2 catalyst has an extremely low metal content of 2.43%. • The Tafel slope is 67 mV·dec−1 when Ru/C-2 is employed as a HER catalyst. • The mass activity is larger than 20 wt% Pt/C when the overpotential exceeds 0.18 V. [ABSTRACT FROM AUTHOR]

Design of catalysts with advanced structures has been extensively studied. Mesocrystal structure with the uniform crystal orientation shows special properties in electrocatalysis. Herein, PtRu mesocrystal was synthesized on F doped graphene by wet chemical method. In this reaction system, silicon nanowires and hydrofluoric acid were used to form Si - H bonds, which served as reducing agents to reduce Pt and Ru ions and grow PtRu particles on reduced graphene oxide (rGO). The electrochemical results showed that the PtRu/rGO catalyst had a favourable electrocatalytic performance on methanol oxidation reaction. The corresponding mass activity reached 739 mA mg−1 Pt , which was 2.23 times as large as 20% commercial platinum carbon (Pt/C, 332 mA mg−1 Pt). Its stability and toxicity resistance were also much better than those of commercial Pt/C, showing a great prospect in practice applications. Furthermore, the forming mechanism of PtRu mesocrystal is discussed, which has general implications for the design of superstructure catalysts. [ABSTRACT FROM AUTHOR]

Cobalt sulfide materials are wildly investigated in oxygen evolution reaction (OER). In order to further decrease the cost of the catalysts, cobalt-copper-iron trimetal sulfides (CoCuFe-S) are designed and successfully fabricated via a simple hydrothermal method following a thermal treatment. CoCuFe-S has a three-dimensional nanostructure, which is assembled by numerous nanosheets. Three components are uniformly distributed in the composite. CoCuFe-S with different ratios are employed as OER catalysts and compared with pure Co 9 S 8 , CuS and FeS. The optimal CoCuFe-S-8 catalyst exhibits high and robust activity for OER with a small overpotential of 0.30 V at current density of 10 mA cm −2 and a low Tafel slope of 79 mV·dec −1 . The turnover frequency is 0.27 s −1 and the mass activity is 114 A g −1 at overpotential of 0.30 V, even better than the commercial RuO 2 . In addition, CoCuFe-S-8 catalyst showed long-term durability under 1 M KOH solution. The excellent OER performance may result from the synergistic effect among the three sulfides. The introduction of FeS and CuS are beneficial for the formation of Co 9 S 8 , increasing the conductivity of the catalyst and decreased the adsorption of the oxygen atoms on Co atom. [ABSTRACT FROM AUTHOR]

The SO 3 -CDs/NiFe LDH was synthesized through electrochemical and hydrothermal methods. The P-SO 3 -CDs/NiFe LDH catalyst work electrode was obtained via polarized by an electric field of 10,000 V/cm for 30 mins. After that, sulfonate functional groups selectively enrich at the surface of catalysts. Such sulfonate functional groups have a strong ability to capture proton, exhibit excellent OER performances as confirmed by DFT calculation and experimental results. [Display omitted] • NiFe LDH/CDs composite was employed as OER catalysts. • Electric field polarization is used to regulate the exposed functional groups. • H+ captured from *OH or *OOH species by the sulfonated groups on CDs. • The overpotential is 200 mV@10 mA cm−2 and Tafel slope is 55.2 mV dec−1. • Polarized catalysts reach a high current density than the unpolarized one. Interfacial design and regulation for electrocatalysts can effectively enhance the performance of oxygen evolution reaction (OER). It is still a challenge to search for a simple and easy way to controllably adjust the interface of catalysts. Here we report a new strategy, electric field polarization to regulate the charged functional groups of nickel–iron layered double hydroxide (NiFe LDH)/carbon dots (CDs) composite catalysts. The selectively exposed sulfonate functional groups on CDs under the electric field have regulated the interfacial environment of the composite catalyst. The density function theory (DFT) calculation also reveals that the high electrocatalytic activity can be attributed to H+ capture from *OH or *OOH species by the sulfonated groups on the surface of CDs. Thus, the synergistic effect between the catalytic activity of NiFe LDH and the functional group-modified CDs enhances the OER performance of the composite catalyst, showing low overpotential of 200 mV at 10 mA cm−2 and outstanding kinetics with Tafel slope of 55.2 mV dec−1. Moreover, the polarized composite catalysts can reach a high current density of 51.7 mA cm−2 at 1.46 V vs. reversible hydrogen electrode (RHE), which is 9.2 times higher than the unpolarized one (5.6 mA cm−2). [ABSTRACT FROM AUTHOR]

• Janus Pd-Au NPs are loaded on graphene oxide through reduction of Si-H bonds. • XRD patterns reveal that Pd is under an average tensile strain of +0.32%. • TEM image demonstrates Pd near the Pd-Au interface under +4% tensile strain. • Tensile strain is beneficial to decrease the reaction energy barrier for ORR. • Zinc-air battery catalyzed by Pd-Au/GO exhibits a peak power density up to 276 mW·cm−2. Strain existed in the bimetallic electrocatalysts may modulate the performance of oxygen reduction reaction (ORR). The density function theory calculation here indicates that the tensile strain originated from the mismatch of lattice spacing between Au and Pd is beneficial to decrease the reaction energy barrier for ORR. Pd-Au nanoparticles were uniformly loaded on graphene oxide (Pd-Au/GO) through the reduction of the Si-H bond. The epitaxial growth of Pd on Au leads to Janus nanostructure. X-ray powder diffraction patterns reveal that Pd is under an average tensile strain of +0.32%, while high resolution transmission electron microscopy image demonstrates Pd near the Pd-Au interface under +4% tensile strain. Better ORR performance of Pd-Au/GO is obtained than the commercial Pt/C in the alkaline medium. The tensile strain enables Pd-Au/GO with a half-wave potential of 0.90 V and a high mass activity of 0.526 A mg Pd −1 at 0.9 V, which both are higher than those of the commercial 40 wt% Pt/C and 20 wt% Pt/C. Meanwhile, the zinc-air battery catalyzed by Pd-Au/GO also exhibits a high peak power density up to 276 mW·cm−2 and a long-term durability than those of Pt/C. The preparation of Janus Pd-Au nanoparticles with the strain effect mentioned in this paper may provide ideal path for the synthesis of other types of materials. [ABSTRACT FROM AUTHOR]