Support modification is an important way to improve the activity of the Ru/MgO-based NH synthesis catalyst. This work synthesized 24 composite MgO-based supports of MO-MgO (M = La, Zn, etc.) via a microdrop-confined pyrolysis (MDCPy) method and then prepared the corresponding Cs-Ba-Ru/MO-MgO catalysts using the impregnation method.
View Article and Find Full Text PDFInt J Biol Macromol
September 2024
Single atom catalysts (SACs) excel in various chemical processes, including electrocatalysis and industrial chemistry, due to their efficiency. In contrast to chemically synthesized precursors, biomass offers a greener and more cost-effective approach for SACs fabrication. To date, over forty types of SACs have been synthesized using natural sources like starch, cellulose, lignin, hemicellulose, proteins, and chitin.
View Article and Find Full Text PDFMaximally exploiting the active sites of iridium catalysts is essential for building low-cost proton exchange membrane (PEM) electrolyzers for green H production. Herein, we report a novel microdrop-confined fusion/blasting (MCFB) strategy for fabricating porous hollow IrO microspheres (IrO-PHM) by introducing explosive gas mediators from a NaNO/glucose mixture. Moreover, the developed MCFB strategy is demonstrated to be general for synthesizing a series of Ir-based composites, including Ir-Cu, Ir-Ru, Ir-Pt, Ir-Rh, Ir-Pd, and Ir-Cu-Pd and other noble metals such as Rh, Ru, and Pt.
View Article and Find Full Text PDFIncreasing the loading density of nanoparticles on carbon support is essential for making Pt-alloy/C catalysts practical in H-air fuel cells. The challenge lies in increasing the loading while suppressing the sintering of Pt-alloy nanoparticles. This work presents a 40% Pt-weighted sub-4 nm PtCo/C alloy catalyst via a simple incipient wetness impregnation method.
View Article and Find Full Text PDFFormic acid is receiving intensive attention as being one of the most progressive chemical fuels for the electrochemical reduction of carbon dioxide. However, the majority of catalysts suffer from low current density and Faraday efficiency. To this end, an efficient catalyst of In/Bi-750 with InO nanodots load is prepared on a two-dimensional nanoflake Bi O CO substrate, which increases the adsorption of CO due to the synergistic interaction between the bimetals and the exposure of sufficient active sites.
View Article and Find Full Text PDFThe hydrogen evolution reaction (HER) involves two-step elementary reactions, providing an opportunity to establish dual-site synergistic catalysts. This work demonstrates carbon-supported Pt single atoms and clusters (Pt-NPC) as an efficient catalyst for acidic HER, which exhibits an ultralow Tafel slope of 12.5 mV/dec and an overpotential of 24 mV at 10 mA/cm with an ultralow platinum content of 3.
View Article and Find Full Text PDFLow-temperature catalytic CO oxidation is an important chemical process in versatile applications, such as the H utilization for low-temperature H air fuel cells. Pt-group metal catalysts are efficient but highly cost-consuming. This work demonstrates an excellent and sixpenny catalyst with earth-abundant Ni and Ce, in which Ni ions are atomically incorporated into the CeO matrix (Ni-Ce-O) by synchronous spray-pyrolysis (SSP) of mixture nitrates of Ni and Ce.
View Article and Find Full Text PDFSuperelastic silk fibroin (SF)-based aerogels can be used as multifunctional substrates, exhibiting a promising prospect in air filtration, thermal insulation, and biomedical materials. However, fabrication of the superelastic pure SF aerogels without adding synthetic polymers remains challenging. Here, the SF micro-nano fibrils (SMNFs) that preserved mesostructures are extracted from SF fibers as building blocks of aerogels by a controllable deep eutectic solvent liquid exfoliation technique.
View Article and Find Full Text PDFIn this work, we introduce Fe and Ni into Co-MOF to construct a kind of multicomponent phosphide hollow architecture with walls assembled by nanosheets. The multicomponent nature can enhance the intrinsic catalytic activity, while the sheet-like surface and inter-sheet voids provide a large active area, which is beneficial for electrolyte penetration and gas generation. As expected, the optimized product has catalytic hydrogen evolution reaction (HER) overpotentials of 105 and 161 mV at current densities of 10 and 100 mA cm, respectively, and maintained long-term stability for over 100 hours at 10 mA cm current densities.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
November 2022
The two-dimensional nanosheets are conducive to not only endow opened surfaces for loading active metal atoms but also boost the mass transfer for the heterogeneous reactions. The challenge is how to load and stabilize single-atoms on nanosheets in high-areal densities. This work reports an efficient micro-gas blasting (MGB) strategy to access versatile noble metal single-atoms/metal oxide nanosheets, including Ir /CoO , Pd /CeO , etc.
View Article and Find Full Text PDFThe properties of supports have a significant effect on the activity of noble metal single atoms. In this work, Co-doped CeO-supported single-atom Pt catalysts (Pt/Co-CeO) have been acquired by a synchronous pyrolysis/deposition route and demonstrated to promote low-temperature oxidation of CO. Revealed by a model reaction of 1% CO + 1% O + 98% He at a space velocity of 12,000 mL/g/h, CO conversion (100 °C) acquired on a (0.
View Article and Find Full Text PDFACS Appl Mater Interfaces
February 2021
Ruthenium nanocrystals with small size and special morphology are of great interest in various catalytic reactions due to their high activities. However, it is still a great challenge to downsize these nanocatalysts to a sub-nano scale (<2 nm). Herein, we reported a synthesis of ultrasmall size and uniform Ru nanoparticles through a rapid one-pot method.
View Article and Find Full Text PDFSelective reduction of ketone/aldehydes to alcohols is of great importance in green chemistry and chemical engineering. Highly efficient catalysts are still demanded to work under mild conditions, especially at room temperature. Here we present a synergistic function of single-atom palladium (Pd) and nanoparticles (Pd) on TiO for highly efficient ketone/aldehydes hydrogenation to alcohols at room temperature.
View Article and Find Full Text PDFDevelopment of Pt group metal-free catalysts for low-temperature CO oxidation remains critical. In this work, active and stable mesoporous Cu-Ce-O solid solutions are prepared by using spray pyrolysis. The specific surface areas and pore volumes reach as high as 170 m g and 0.
View Article and Find Full Text PDFEfficient, abundant and low-cost catalysts for the oxygen evolution reaction (OER) are required for energy conversion and storage. In this study, a doping-etching route has been developed to access defect rich Fe-Co-Al (Fe-Co-Al-AE) ternary hydroxide nanosheets for superior electrochemical oxygen evolution. After partial etching of Al, ultrathin Fe Co Al -AE electrocatalysts with a rich pore structure are obtained with a shift of the cobalt valence state towards higher valence (Co →Co ), along with a substantial improvement in the catalytic performance.
View Article and Find Full Text PDFA mesoporous MnCo O electrode material is made for bifunctional oxygen electrocatalysis. The MnCo O exhibits both Co O -like activity for oxygen evolution reaction (OER) and Mn O -like performance for oxygen reduction reaction (ORR). The potential difference between the ORR and OER of MnCo O is as low as 0.
View Article and Find Full Text PDFCarbon-based transition-metal oxides are considered as an appropriate anode material candidate for lithium-ion batteries. Herein, a simple and scalable dry production process is developed to produce carbon-encapsulated 3D net-like FeO /C materials. The process is simply associated with the pyrolysis of a solid carbon source, such as filter paper, adsorbed with ferrite nitrate.
View Article and Find Full Text PDFGraphene-based hybrid nanostructures possess many advantages in the field of electrochemical energy applications. In this work, a facile and efficient hydrothermal approach has been developed for the preparation of NiFe alloy nanoparticles/rGO hybrid nanostructures, in which the nanoparticles are well combined with rGO nanosheets and the size of the nanoparticles is about 100 nm. Moreover, the electrochemical oxygen evolution reaction (OER) tests confirmed that the obtained NiFe/rGO hybrid nanostructures possess notably higher activity than both the rGO-free NiFe nanoparticles and pure Ni/rGO hybrids, and the optimal NiFe ratio is 2:1.
View Article and Find Full Text PDFPtAg alloyed nanostructural catalysts were firstly prepared by co-reduction of AgNO3 and H2PtCl6 precursors in growth solution using a seed-mediated method. By simply changing the molar ratio of the metal precursors, the morphologies of the porous alloyed nanocrystals can be tuned from multipetals to multioctahedra. Simultaneously, the alloy composition can be varied from Pt76Ag24 to Pt66Ag34.
View Article and Find Full Text PDFPreparing nonprecious metal catalysts with high activity in the oxygen reduction reaction (ORR) can promote the development of energy conversion devices. Support-free porous Mn2 O3 was synthesized by a facile aerosol-spray-assisted approach (ASAA) and subsequent thermal treatment, and exhibited ORR activity that is comparable to commercial Pt/C The catalyst also exhibits notably higher activity than other Mn-based oxides, such as Mn3 O4 and MnO2 . The rotating ring disk electrode (RRDE) study indicates a typical 4-electron ORR pathway on Mn2 O3 .
View Article and Find Full Text PDFNoble metal nanoparticles (NPs) with 1-5 nm diameter obtained from NaHB4 reduction possess high catalytic activity. However, they are rarely used directly. This work presents a facile, versatile, and efficient aerosol-spray approach to deliver noble-metal NPs into metal oxide supports, while maintaining the size of the NPs and the ability to easily adjust the loading amount.
View Article and Find Full Text PDFTransition metal oxides are widely used in solar cells, batteries, transistors, memories, transparent conductive electrodes, photocatalysts, gas sensors, supercapacitors, and smart windows. In many of these applications, large surface areas and pore volumes can enhance molecular adsorption, facilitate ion transfer, and increase interfacial areas; the formation of complex oxides (mixed, doped, multimetallic oxides and oxide-based hybrids) can alter electronic band structures, modify/enhance charge carrier concentrations/separation, and introduce desired functionalities. A general synthetic approach to diverse mesoporous metal oxides is therefore very attractive.
View Article and Find Full Text PDFA facile one-step solution reaction route for growth of novel MoS2 nanorose cross-linked by 3D rGO network, in which the MoS2 nanorose is constructed by single-layered or few-layered MoS2 nanosheets, is presented. Due to the 3D assembled hierarchical architecture of the ultrathin MoS2 nanosheets and the interconnection of 3D rGO network, as well as the synergetic effects of MoS2 and rGO, the as-prepared MoS2-NR/rGO nanohybrids delivered high specific capacity, excellent cycling and good rate performance when evaluated as an anode material for lithium-ion batteries. Moreover, the nanohybrids also show excellent hydrogen-evolution catalytic activity and durability in an acidic medium, which is superior to MoS2 nanorose and their nanoparticles counterparts.
View Article and Find Full Text PDFAbundant iron group metal oxides and their composites possess great potential in the application of electrochemical energy storage and conversion. In this work, we obtained Co-Fe-O composites/reduced graphene oxides (CFO/rGO) hybrid structures, engineered their compositions, phase, and structures by a facile hydrothermal route, and studied their composition-dependent activity for electrochemical oxygen evolution reaction (OER) in alkaline media. It is found that synergetic effects bring a clear decrease in overpotential and Tafel slope for CFO/rGO catalysts in comparison with monometallic composition/rGO catalysts.
View Article and Find Full Text PDFIn this work, a general, facile, successive and eco-friendly method for multilayer nanostructures has been established for the first time. We take full advantage of the structural and compositional character of M1@M2 (M1 = Co, Ni, M2 = Pt/Pd, Pt, Pd and Au) core-shell nanostructures to prepare a series of reusable tremella-like M1@M2@M1(OH)2 three layer core-shell or yolk-shell nanocomposites with a magnetic core, a porous noble metal shell, and an ultrathin cobalt or nickel hydroxide shell. We evaluated their catalytic performance using a model reaction based on the reduction of 4-nitrophenol.
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