Advancements in single-atom-based catalysts are crucial for enhancing oxygen evolution reaction (OER) performance while reducing precious metal usage. A comprehensive understanding of underlying mechanisms will expedite this progress further. Here we report Ir single atoms coordinated out-of-plane with dimethylimidazole (MI) on CoFe hydroxide (Ir/(Co,Fe)-OH/MI).
View Article and Find Full Text PDFThe first coordination shell is considered crucial in determining the performance of single atom catalysts (SACs), but the significance of the second coordination shell has been overlooked. In this study, we developed a post-doping strategy to realize predictable and controlled modulation on the second coordination shell. By incorporating a P atom into the second coordination shell of a porphyrin-like Pt SAC, the charge density at the Fermi level of Pt single atom increases, enhancing its intrinsic activity.
View Article and Find Full Text PDFThe microscopic reaction pathway plays a crucial role in determining the electrochemical performance. However, artificially manipulating the reaction pathway still faces considerable challenges. In this study, we focus on the classical acidic water oxidation based on RuO catalysts, which currently face the issues of low activity and poor stability.
View Article and Find Full Text PDFA new strategy that can effectively increase the nitrogen reduction reaction performance of catalysts is proposed and verified by tuning the coordination number of metal atoms. It is found that the intrinsic activity of Mn atoms in the manganese borides (MnB) increases in tandem with their coordination number with B atoms. Electron-deficient boron atoms are capable of accepting electrons from Mn atoms, which enhances the adsorption of N on the Mn catalytic sites (*) and the hydrogenation of N to form *NNH intermediates.
View Article and Find Full Text PDFAnode materials with high-rate performances and good electrochemical stabilities are urgently required for the grid-scale application of lithium-ion batteries (LIBs). Theoretically, transition metal borides are desirable candidates because of their appropriate working potentials and good conductivities. However, the reported metal borides exhibit poor performances owing to their lack of favorable Li storage sites and poor structural stabilities during long-term charging/discharging.
View Article and Find Full Text PDFLayered oxides are widely used as the electrode materials for metal ion batteries. However, for large radius size ions, such as Zn and Al, the tightly stacked layers and poor electrical conductivity of layered oxides result in restricted number of active sites and sluggish reaction kinetics. In this work, a facile in-situ construction strategy is provided to synthesize layered oxide nanosheets/nitrogen-doped carbon nanosheet (NC) heterostructure, which shows larger interlayer spacing and better electrical conductivity than the layered oxides.
View Article and Find Full Text PDFLithium metal anodes face several challenges in practical applications, such as dendrite growth, poor cycle efficiency, and volume variation. 3D hosts with lithiophilic surfaces have emerged as a promising design strategy for anodes. In this study, inspiration from the intrinsic isotropy, chemical heterogeneity, and wide tunability of metallic glass (MG) is drew to develop a 3D mesoporous host with a lithiophilic surface.
View Article and Find Full Text PDFElectrolyte modulation and electrode structure design are two common strategies to suppress dendrites growth on Li metal anode. In this work, a self-adaptive electrode construction method to suppress Li dendrites growth is reported, which merges the merits of electrolyte modulation and electrode structure design strategies. In detail, negatively charged titania nanosheets with densely packed nanopores on them are prepared.
View Article and Find Full Text PDFLithium-sulfur (Li-S) batteries are one of the emerging candidates for energy storage systems due to their high theoretical energy density and the abundance/nontoxicity/low cost of sulfur. Compared with conventional lithium-ion batteries, multiple new challenges have been brought into this advanced battery system, such as polysulfide shuttling in conventional polyolefin separators and undesired lithium dendrite formation of the Li metal anode. These issues severely affect the cell performance and impede their practical applications.
View Article and Find Full Text PDFThe growth of ultrathin 1D inorganic nanomaterials with controlled diameters remains challenging by current synthetic approaches. A polymer chain templated method is developed to synthesize ultrathin Bi O CO nanotubes. This formation of nanotubes is a consequence of registry between the electrostatic absorption of functional groups on polymer template and the growth habit of Bi O CO .
View Article and Find Full Text PDFElectroreducting nitrate (NO) into ammonia (NH), i.e. NORA, can not only relieve NO pollution but also produce high value-added NH.
View Article and Find Full Text PDFReducing the particle size of active material is an effective solution to the poor rate performance of the lithium-ion battery. In this study, we proposed a facile strategy for the preparation of nano-graphite as an anode for a lithium-ion battery via the rapid mechanical pulverization method. It is the first time that diamond particle was selected as the medium to achieve high preparation efficiency and low energy consumption.
View Article and Find Full Text PDFThree dimensional (3D) hosts have been recognized as effective current collectors for Li metal anodes because of their physical suppression of the lithium dendrites growth. A lithiophilic surface layer on them could increase the Li metal nucleation sites, further regulating the genuine plating of Li metal. The current strategies to construct this lithiophilic layer on 3D structure is complex and not suitable for the scalable fabrication of Li metal anode.
View Article and Find Full Text PDFJ Colloid Interface Sci
October 2022
Chemical fixation of CO with epoxides is an effective option to achieve sustainable synthesis of cyclic organic carbonates. Although metal-organic frameworks (MOFs) are promising catalysts for this reaction, their low stability in aqueous solutions makes this application infeasible. In an effort to overcome this limitation, cobalt-based metal-organic framework (Co(II)MOF) nanoribbons have been prepared by coordinating the Co(II) ions with a new ligand (CHNO) full of oxygen and nitrogen moieties.
View Article and Find Full Text PDFA method for creating genuine nanopores in high area density on monolayer two-dimensional (2D) metallic oxides has been developed. By use of the strong reduction capability of hydroiodic acid, active metal ions, such as Fe and Co, in 2D oxide nanosheets can be reduced to a divalent charge state (2+). The selective removal of FeO and CoO metal oxide units from the framework can be tuned to produce pores in a range of 1-4 nm.
View Article and Find Full Text PDFHere, the synthesis of a series of pure phase metal borides is reported, including WB, CoB, WCoB, and W CoB , and their surface reconstruction is studied under the electrochemical activation in alkaline solution. A cyclic voltammetric activation is found to enhance the activity of the CoB and W CoB precatalysts due to the transformation of their surfaces into the amorphous CoOOH layer with a thickness of 3-4 nm. However, such surface transformation does not happen on the WB and WCoB due to their superior structure stability under the applied voltage, highlighting the importance of metal components for the surface reconstruction process.
View Article and Find Full Text PDFTransition metal borides are considered as promising electrocatalysts for water splitting due to their metallic conductivity and good durability. However, the currently reported monometallic and noncrystalline multimetallic borides only show generic and monofunctional catalytic activity. In this work, the authors design and successfully synthesize highly crystalline ternary borides, Mo NiB , via a facile solid-state reaction from pure elemental powders.
View Article and Find Full Text PDFACS Sustain Chem Eng
March 2022
The advent of the COVID-19 pandemic has initiated a radical attention shift of society toward the severe consequences it has had over human health, shadowing a symmetrically, if not more, important issue of the rapid intensification in the amount of plastic waste that has been generated over the due course of time. Such a growth in the plastic footprint across the globe has led to a carbon positive environment with an increased amount of greenhouse gases (GHGs) released due to the processing of the waste plastic. We aim to address and provide our perception to this pressing challenge that can be decoded via the advancement of upcycling technologies, utilized and augmented worldwide.
View Article and Find Full Text PDFThe interfacial properties within a composite structure of membranes play a vital role in the separation properties and application performances. Building an interlayer can facilitate the formation of a highly selective layer as well as improve the interfacial properties of the composite membrane. However, it is difficult for a nanomaterial-based interlayer to increase the flux and retention of nanofiltration membranes simultaneously.
View Article and Find Full Text PDFControlled synthesis of noble metal nanoparticles with well-defined size and good dispersion on supports has been a long-standing challenge in heterogeneous catalysis. Here we report a facile photo-assisted Hin situ reduction process to synthesize monodispersed Pd nanoparticles with 2-4 nm size on photo-insensitive SmO rare-earth metal oxide with nanorod morphology. Thanks to the contribution of UV irradiation, the photoelectrons generation in the SmO support accelerates the H reduction of Pd ions into Pd and stabilize the growth of very small Pd nanoparticles homogeneously dispersed on the support.
View Article and Find Full Text PDFACS Appl Mater Interfaces
August 2020
A well-formed solid electrolyte interface (SEI) is critical for achieving long-term cycling stability in lithium-ion batteries (LIBs). However, the SEI remains the poorly understood component in LIBs especially under dynamic conditions. Here, scanning electrochemical microscopy (SECM) was applied to study the spontaneous reaction on a graphite electrode, SEI formation in the first cycle, SEI evolution during 10 cycles, and the stability of the as-formed SEI in the electrolyte.
View Article and Find Full Text PDFTo substitute precious metal with non-precious electrocatalysts, that can work efficiently, still remains a great challenge. Herein, we fabricated the series of nitrogen doped carbon (NC) and CoFe-NC core-shell architectures to produce dual-functionality towards oxygen reduction/evolution reactions and ultimately for Zn-air battery. The addition of NC tends to prevent the reduction of Co/Fe nanoparticles during pyrolysis which not only provide improved catalytic sites but also boost the specific surface area, graphitization degree, electron and mass transfer capacity.
View Article and Find Full Text PDFThe scalable and high-efficiency production of 2D materials is a prerequisite to their commercial use. Currently, only graphene and graphene oxide can be produced on a ton scale, and the inability to produce other 2D materials on such a large scale hinders their technological applications. Here we report a grinding exfoliation method that uses micro-particles as force intermediates to resolve applied compressive forces into a multitude of small shear forces, inducing the highly efficient exfoliation of layer materials.
View Article and Find Full Text PDFA productive and novel method for fabricating stretchable transparent heaters with recognised thermochromic properties using commercially available thermochromic ink (TM-55-blue) and silver nanowire (AgNW)-coated polydimethylsiloxane (PDMS) is proposed. Lower resistance, elevated heat generation, and higher transparencies were the expected essential prerequisites for the fabrication of items such as smart windows and window defrosters. AgNW-coated PDMS (hereafter PH devices) satisfied the essential prerequisites but did not produce sufficient color change.
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