Search

In the pursuit of stable, high performance Ni-based oxygen evolution reaction (OER) electrocatalysts, modifying the local chemical compositions or fabricating hybrid nanostructures to generate abundant interfaces for improving the water oxidation activity of electrocatalysts has emerged as an effective strategy. Herein, we report the facile development of a Ni3S2-CeO2 hybrid nanostructure via an electrodeposition method. Benefiting from the strong interfacial interaction between Ni3S2 and CeO2, the electron transfer is notably improved and the water oxidation activity of Ni3S2 nanosheets is significantly enhanced. In 1.0 M KOH, the Ni3S2-CeO2 electrocatalyst achieves a current density of 20 mA cm–2 at a low overpotential of 264 mV, which is 92 mV lower than that of Ni3S2. Moreover, Ni3S2-CeO2 exhibits superior electrochemical stability. Density functional theory calculations demonstrate that the enhanced OER electrocatalytic performance of Ni3S2-CeO2 can be ascribed to an increase in the binding strength of the reaction intermediates at the Ni3S2-CeO2 interface.

Bimetallic nanoparticle (NP)-supported catalysts for use in the hydrogenation reaction has received growing attention on account their excellent catalytic performance. In the present work, bimetallic Au–Pt and monometallic Pt/Au NPs were supported on the Zr-based metal–organic framework UiO-67 via a simple impregnation–reduction method. The catalytic performance of the catalysts for selective 1,3-butadiene (1,3-BD) hydrogenation was influenced by the space velocity, reaction temperature and Au/Pt molar ratio. Whilst bimetallic AuPt/UiO-67-3 displayed catalytic activity similar to that of Pt/UiO-67 for selective 1,3-BD hydrogenation, the former also exhibited much higher selectivity toward total butenes than the latter. The AuPt/UiO-67-3 catalyst with a 1.1:1.0 Au/Pt molar ratio exhibited the best catalytic activity and butene selectivity for selective 1,3-BD hydrogenation at 100 °C with a space velocity of 117 L/(h gcat). This work provides a practical example of novel and efficient bimetallic supported catalysts.

Supported bimetallic nanoparticles (NPs) are extensively used as efficient oxidation catalysts. A series of Au–Ni bimetallic alloy NP catalysts with Au:Ni mole ratios varying from 1:0.35 to 1:4.76 was successfully synthesized via impregnation and H2 reduction. The catalysts are supported by a metal–organic framework MIL-101. For comparison, monometallic Au/MIL-101 with an Au loading amount of 2.97 wt% and Ni/MIL-101 with a Ni loading amount of 2.11 wt% were also prepared. The catalysts were thoroughly characterized through X-ray diffraction, N2 adsorption–desorption isotherms, transmission electron microscopy (TEM), scanning TEM with line mapping energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and inductively coupled plasma atomic emission. Characterization results suggested that the AuNi bimetallic NP catalysts were homogeneously deposited on the MIL-101 surface, and an AuNi alloy structure was formed. The bimetallic Au–Ni and monometallic catalysts were evaluated for the oxidation of benzyl alcohol under O2 atmosphere. The bimetallic AuNi/MIL-101-1 catalyst displayed a higher catalytic activity under identical conditions compared with the monometallic catalysts due to the synergistic effects between Au and Ni metals. The Au–Ni/MIL-101-1 catalyst with an Au–Ni mole ratio of 1:0.35 exhibited the highest turnover frequency value of 15.4 h−1 for the oxidation of benzyl alcohol. In addition, the bimetallic AuNi/MIL-101-1 catalysts could be recovered easily by centrifugation and used repetitively for at least four times. These features make the catalysts particularly attractive in benzaldehyde synthesis.

Developing active, stable and cost-effective transition metal electrocatalysts for increasing the rate of the oxygen evolution reaction (OER) is crucial for renewable energy conversion, but still remains challenging. In this communication, we report a novel Cu-nanoparticle decorated CoS2 nanoneedle array on Ti mesh (Cu@CoS2/TM) as an efficient electrocatalyst for alkaline water oxidation. Benefiting from a large active surface area and a strong interfacial interaction between Cu and CoS2, Cu@CoS2/TM exhibits excellent OER performance in alkaline media with only a small overpotential of 277 mV to deliver 50 mA cm−2. This value is 62 mV less than that of CoS2/TM. Cu@CoS2/TM achieves a high turnover rate of 0.25 mol O2 s−1 at 400 mV, which is approximately 1.7 times higher than that of CoS2/TM. Notably, Cu@CoS2/TM also demonstrates superior long-term electrochemical stability.

Two novel sandwich-type (phthalocyaninato)(porphyrinato) europium double-decker complexes, namely Eu(Pc)[(NHC 8 H 17 )PP] ( 1 ) and Eu(Pc)[(NHC 8 H 17 ) 4 PP] ( 2 ), have been designed and synthesized. Their self-assembly properties, in particular the effect of the numbers of octylaminophenyl groups on the morphology of self-assembled nanostructures of these double-decker complexes, have been comparatively and systematically studied. Depending mainly on the hydrogen bond between one octylaminophenyl group at meso -attached phenyl group of porphyrin ligand in 1 and one aza-nitrogen atom of the phthalocyanine ring in the neighboring molecule of 1 , 1 self-assembled into nano-rods with J -type aggregation. In good contrast, introduction of four octylaminophenyl groups onto the m eso -attached phenyl groups of the porphyrin ligand in 2 , induces more N–H⋯N hydrogen bonds between neighboring molecules of 2 , induces the formation of nano-sheets with H -type aggregation. These results clearly imply the effective influence of hydrogen bond numbers on the molecular stacking mode and the morphology of the assembled nanostructures.