In this work, the Cu single-atom catalysts (SACs) supported by metal-oxides (AlO-Cu, CeO-Cu, and TiO-Cu) are used as theoretical models to explore the correlations between electronic structures and CORR performances. For these catalysts, the electronic metal-support interaction (EMSI) induced by charge transfer between Cu sites and supports subtly modulates the Cu electronic structure to form different highest occupied-orbital. The highest occupied 3d orbital of AlO-Cu enhances the adsorption strength of CO and weakens C-O bonds through 3d-π* electron back-donation.
View Article and Find Full Text PDFAmmonia borane (NHBH, AB) is considered a promising chemical hydrogen storage material. The development of efficient, stable, and economical catalysts for AB hydrolysis is essential for realizing the hydrogen energy economy. In this study, a series of p-p heterojunction catalysts, labeled M (P/S/Cl)-CuCoO, were fabricated using the high-temperature vapor phase method to achieve anionic interface gradient doping.
View Article and Find Full Text PDFProducing hydrogen through water electrolysis represents a clean and sustainable solution that is crucial in addressing the energy crisis. Nonetheless, the slow process of water electrolysis leads to large different kinetics for hydrogen evolution reaction (HER) under different pH solutions. Here, we designed surface modified metallic X-Cu catalysts (X = F, Cl, Br) with different non-metallic elements on nickel foam (NF) using an electrochemical deposition method, which realizes high performance for all-pH range.
View Article and Find Full Text PDFImprovement in the durable and active low-Pt nanocatalysts for oxygen reduction reaction (ORR) is the essential target for clean energy. Herein, an efficient CeO supported PtCu alloy catalyst (PtCu/CeO-C) for ORR in acid media is developed. The CeO support can effectively anchor the PtCu particles and inhibit their migration during the long-life cycling, which is beneficial to the catalytic performance.
View Article and Find Full Text PDFPt-based intermetallics are regarded as highly efficient electrocatalysts for oxygen reduction reaction (ORR). However, Pt-based intermetallics with different Pt: M atomic ratios have different atomic arrangements and crystal structures, which will change the electronic structure and coordination environment of Pt, thus affecting the electrocatalytic activity. In this work, we prepared L1-PtCo and L1-PtCo intermetallic catalysts by modulating the molar ratio of Pt and Co precursors using a thermal annealing method.
View Article and Find Full Text PDFACS Appl Mater Interfaces
April 2024
The inadequate electrical conductivity of metal sulfides, along with their tendency to agglomerate, has hindered their use in energy storage and catalysis. The construction of a heterojunction can ameliorate these deficiencies to some extent. In this paper, MnS-BaS heterojunction catalysts were prepared by a hydrothermal method, which is a simple and inexpensive process.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
April 2024
Carbon dots (CDs) possess the merits such as energy efficiency, green sustainability and environmental friendliness, comparing with top-down synthesis methods at higher pressure or temperature condition. Here, a variety of emission states CDs were prepared by using the method of room temperature chemistry by selecting green raw materials such as glucose, p-phthalaldehyde and m-diethylaminophenol. The luminescence mechanism was studied in detail.
View Article and Find Full Text PDFNitrogen-doped carbon is considered one of the most promising oxygen reduction catalysts due to its low cost and high activity, however, it still falls short of Pt/C. In this study, we report a strategy for the preparation of highly reactive N-doped hierarchical porous carbon by primary pyrolysis using zinc acetate as a stand-alone zinc source and amino-rich reactants as carbon and nitrogen sources to introduce Zn-N structures into mesoporous structures generated by the hard template method using the strong coordination of zinc and amino groups. Benefited from the simultaneous optimization of the hierarchical porous structure and nitrogen-doping, the half-wave potential of Zn(OAc) -DCD/HPC is as high as 0.
View Article and Find Full Text PDFThe design of high-performance oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) dual-functional catalysts is not only important for the further applications of zinc-air batteries (ZABs) but also a major challenge in the field of energy conversion. The cheap 1,2,4-triazole (1,2,4-TZ) can be decomposed easily by heat, making it a high research value in carbon catalysts derived from metal-organic frameworks (MOFs). Here, CoN particles encapsulated at the top of N-doped carbon nanotubes (CoN@NCNTs) were conveniently prepared by 1,2,4-TZ-assisted pyrolysis of Co-MOF-74 for the first time.
View Article and Find Full Text PDFACS Appl Mater Interfaces
April 2023
Water electrolysis in alkaline media is the most promising technology for hydrogen production, but efficient electrocatalysts are required to reduce the overpotential in HER and OER processes. In this work, the multicomponent transition metal catalyst Cr-Cu/CoO was loaded on copper foam by electrodeposition and annealing, and the catalyst exhibited excellent electrochemical activity. The HER overpotential is 21 mV and the OER overpotential is 252 mV at a current density of 10 mA cm.
View Article and Find Full Text PDFDeveloping highly durable and active catalysts with the morphology of structurally robust nanoframes toward oxygen reduction reaction (ORR) and methanol oxidation reaction (MOR) in acidic environment is crucial but still a great challenge to completely achieve in a single material. Herein, PtCuCo nanoframes (PtCuCo NFs) with internal support structures as enhanced bifunctional electrocatalysts were prepared by a facile one-pot approach. PtCuCo NFs exhibited remarkable activity and durability for ORR and MOR owing to the ternary compositions and the structure-fortifying frame structures.
View Article and Find Full Text PDFTo reduce the over-dependence on Pt, Pd-based catalysts have become one of the most effective candidates for oxygen reduction reaction (ORR). In order to further accelerate the ORR kinetics and strengthen the catalytic performance of Pd catalysts, component optimization and morphology design have been adopted. Although great progress has been made, it is still difficult to obtain porous ultrathin nanosheets with excellent performance by a simple method.
View Article and Find Full Text PDFTransition-metal oxides with a strain effect have attracted immense interest as cathode materials for fuel cells. However, owing to the introduction of heterostructures, substrates, or a large number of defects during the synthesis of strain-bearing catalysts, not only is the structure-activity relationship complicated but also their performance is mediocre. In this study, a mode of strain introduction is reported.
View Article and Find Full Text PDFACS Appl Mater Interfaces
March 2021
Electrocatalytic water splitting is a promising technology for large-scale hydrogen production. However, it requires efficient catalysts to overcome the large overpotentials in the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Herein, we report a novel heterostructure catalyst CoS/CuS on copper foam (CoS/CuS/CF) with multistep impregnation and electrodeposition.
View Article and Find Full Text PDFSpark ablation in gas (SAG) technology has the characteristics of being green, fast quenching, fast dynamics and specializes in producing metallic nanoparticles with a clean surface, small size, and abundant defects. In this study, Ag nanoparticles were prepared SAG and loaded on a carbon fiber through nitrogen flow. The effect of the carrier gas flow rate and deposition time on the particle size and the dispersibility of the as-prepared Ag nanoparticles on the carbon fiber by SAG were investigated, and the hydrogen evolution reaction (HER) performances of the samples in acidic media were further studied.
View Article and Find Full Text PDFThe development of efficient, stable, and low-cost catalytic material for the oxygen reduction reaction (ORR) is currently highly desirable but challenging. In this work, based on first-principles calculation, the stabilities, catalytic activities and catalytic mechanisms of isolated Au atom supported on defective porous BN (p-BN) have been studied in detail. The results reveal that the defective p-BN anchor Au atom strongly to ensure the stability of Au/p-BN.
View Article and Find Full Text PDFACS Appl Mater Interfaces
November 2019
High magnetization materials are in great demand for the fabrication of advanced multifunctional magnetic devices. Notwithstanding this demand, the development of new materials with these attributes has been relatively slow. In this work, we propose a new strategy to achieve high magnetic moments above room temperature.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
December 2019
In this work, we presented a facile microwave method to prepare blue emitting carbon dots (CDs) using lysine as carbon source and realized the specific detection of seven types of antibiotics by CDs and Al ions via a two-step method. The CDs have good solubility in water and their excitation spectra are exactly coincided with the absorption of some typical antibiotics, which leads to the fluorescence quenching of CDs (OFF state). The inhibition mechanism of fluorescence is induced by the combination of inner filtering effect (IFE) and static quenching effect (SQE).
View Article and Find Full Text PDFDeveloping efficient and earth-abundant electrocatalysts for the oxygen evolution reaction (OER) is still a big challenge. Here, perovskite LaSrNiFeO nanoparticles were rationally designed and synthesized by the sol-gel method with an average size around 25 nm, and it has a remarkable intrinsically activity and stability in 1 M KOH solution. Compared with other perovskite (LaNiO, LaFeO, and LaNiFeO) catalysts, LaSrNiFeO exhibits superior OER performance, smaller tafel slope and lower overpotential.
View Article and Find Full Text PDFACS Appl Mater Interfaces
July 2018
Five percent Fe-doped InO films were deposited using a pulsed laser deposition system. X-ray diffraction and transmission electron microscopy analysis show that the films deposited under oxygen partial pressures of 10 and 10 Torr are uniform without clusters or secondary phases. However, the film deposited under 10 Torr has a Fe-rich phase at the interface.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
October 2018
Boron carbon oxynitride quantum dots (BCNO QDs) with blue emission were prepared via the template of SBA-15 (a typical mesoporous silica). A modulated photoluminescence sensor was developed based on the different quenching effects of Cu or Hg ions on the luminescence intensity of BCNO QDs. The Cu or Hg ions have an interaction with BCNO QDs due to the electrons transfer between the BCNO and Cu or Hg ions, and the detection limit of Cu or Hg ion concentration can be as less as 10 nM.
View Article and Find Full Text PDFNanomaterials (Basel)
April 2018
In this paper, spherical carbon dots (CDs) with distinct compositions and surface states have been successfully synthesized by a facile microwave method. From the fluorescence spectra, several characteristic luminescence features have been observed: surface amino groups are dominant in the whole emission spectra centering at 445 nm, and the fingerprint emissions relevant to the impurity levels formed by some groups related to C and N elements, including C-C/C=C (intrinsic C), C-N (graphitic N), N-containing heterocycles (pyridine N) and C=O groups, are located around 305 nm, 355 nm, 410 nm, and 500 nm, respectively. Those fine luminescence features could be ascribed to the electron transition among various trapping states within the band structure caused by different chemical bonds in carbon cores, or functional groups attached to the CDs' surfaces.
View Article and Find Full Text PDFWe report on the controlled growth of novel BN-coated Ca(1-x)Sr(x)S:Eu nanowires via a solid-liquid-solid process. The Ca(1-x)Sr(x)S solid solution forms as one-dimensional nanowires and has been coated with homogeneous protective BN nanolayers. The structure and luminescence properties of this new nanocomposite have been systematically investigated.
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