ChemPhysMater最新文献

Multifunctional catalysts that exhibit high catalytic performance for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and oxygen reduction reaction (ORR) in a single material hold great promise for broad-spectrum applications, including overall water splitting, fuel cells, and metal–air batteries. In this first-principles study, Cu₃N is computationally demonstrated as a multifunctional electrocatalyst for the HER, OER, and ORR owing to the unique coordination of N and Cu atoms on the (001) surface. Cu₃N exhibits better HER catalytic activity than noble Pt-based catalysts. Furthermore, its OER and ORR catalytic activity is comparable to that of commercialized unifunctional catalysts, and its 4e^– pathway selectivity is high during the ORR. The catalytic performance of the ORR is significantly improved by the introduction of vacancy defects. The integration of highly efficient HER, OER, and ORR catalytic performance in earth-abundant Cu₃N not only opens an avenue for developing cost-efficient omnipotent catalysts but also facilitates advances in clean and renewable energy.

Thanks to the synergistic effect, the bimetallic catalysts show better catalytic activity than the single metal catalysts and become a focus of research in heterogeneous catalysis. In this study, we successfully prepared Pd-Pt icosahedra which show high peroxidase-like activity under the synergistic effects of Pd and Pt. V_max of the Pd-Pt icosahedra was significantly enhanced by 1.66 times for 3,3’,5,5’-tetramethylbenzidine (TMB) as the substrate and 1.23 times for H₂O₂ as the substrate, compared to that of the Pd icosahedra alone. By harnessing the superior peroxidase-like activity of Pd-Pt icosahedra, we successfully utilized Pd-Pt icosahedral nanozymes in various biological analyses based on colorimetry. In most cases, using a Pd-Pt icosahedra/H₂O₂/TMB system, glucose, glutathione (GSH), acid phosphatase (ACP), and alkaline phosphatase (ALP) were detected over a wide range of 0.05∼0.20 mM, 0∼20 mM, 0∼10 U/L and 0∼12 U/L. In this study, we prepared a novel bimetallic nanozyme that exhibited excellent peroxidase-like activity owing to the bimetallic synergistic effect, thus demonstrating the promising potential of Pd-Pt icosahedra in the field of bioanalysis.

Sodium ion batteries (SIBs) have been widely studied because of their low cost, low standard redox potential, and abundant sodium availability. However, the structural rupture during the Na⁺ insertion/extraction processes and the poor conductivity of the anode material limit its cycling stability and rate capability. Herein, SnSe@C was prepared by high-temperature annealing with dopamine hydrochloride as the carbon source, while SnSe was prepared by a protein reduction method. The carbon layer not only works as a protective layer to limit the volume expansion of SnSe and reduce the dissolution of Na₂Se and poly-selenides generated during the discharge process in the electrolyte, but also as a conductive matrix to expedite electron transfer, thereby boosting the cycling stability and rate capability of SnSe@C. Benefiting from the above advantages, SnSe@C exhibits a specific capacity of 211.3 mAh g⁻¹ at 0.1 A g⁻¹ after 110 cycles and outstanging rate capability (210.1 mAh g⁻¹ at 5.0 A g⁻¹ and capacity retention rate of 63.2% from 0.1 to 1.0 A g⁻¹). This study not only proposes an idea for promoting the cycling stability and rate capability of SnSe, but also paves the way for providing anodic materials with a stable structure for SIBs.

Developing highly efficient catalyst for the hydrogen evolution reaction (HER) and understanding their mechanism is crucial for establishing the hydrogen economy. Carbon-based materials are particularly attractive as HER catalysts because of their abundance and morphological variety. Herein, using density functional theory (DFT) calculations, we propose for the first time a virtual interface consisting of sp² and sp³ orbitals of carbon, for activating the intrinsically inert low-dimensional carbon toward the HER. This hybrid orbital interface is generated by pre-adsorbed hydrogen introduced by the partial hydrogenation of these low-dimensional carbon materials (C₆₀, carbon nanotubes and graphene). The pre-adsorbed hydrogen can activate adjacent carbon atoms to become active sites for the HER. The best performance among these sites is comparable to that of the commercial Pt/C catalyst. Given that the partial hydrogenation of low-dimensional carbon has been experimentally realized, our work provides a simple yet novel concept for HER catalyst design.

Gold nanoparticles (Au NPs) have demonstrated great potential in chemical and biological sensing, catalysis, biomedicine, X-ray computed tomography, and other applications, owing to their unique properties. Au NPs with high-index facets have attracted more attention in the past decade owing to their superior electrocatalytic activity in fuel cells and enhanced performance in surface-enhanced Raman spectroscopy (SERS) applications. This review presents an overview of our achievements in the direct synthesis of Au NPs with controlled shapes in water using cationic surfactants. By deliberately adjusting the nature of the surfactant stabilizers, preformed Au NPs with simple shapes can be readily transformed into Au NPs with complicated shapes with controlled high-index facets by simple seeded growth. The high-index facets of the as-prepared Au NPs can be consistently correlated with their superior performance in the electrooxidation of methanol and ethanol and their enhanced SERS activity.

Cuprous oxide is a potential photocatalyst for the reduction of CO₂. However, its high rate of charge recombination and low ability to adsorb CO₂ limit its activity, particularly when gaseous CO₂ was used. Herein, a Cu-based metal-organic framework (Cu-MOF-74) with high CO₂ adsorption is coated onto Cu₂O nanowires by a topotactic transformation method. The optimized Cu₂O@Cu-MOF-74 composite thin film showed a CH₄ evolution rate 4.5 times higher than that of bare Cu₂O under visible light illumination (>420 nm), with water vapor as the electron donor. Analysis results of electrochemical impedance spectroscopy, transient photocurrent measurements, and fluorescence spectroscopy collectively suggest that the decoration of Cu₂O with Cu-MOF-74 facilitates electron extraction from excited Cu₂O, thereby inducing long-lived photocharges for the reduction of CO₂. This study provides insights into the modification of transition metal oxides for application in photocatalysis by coating the surface with metal-organic frameworks.

Cubic-phase ZrO₂ nanoparticle (NPs) were synthesized using a cost-effective single-pot green combustion method and Helianthus annuus extract, and their properties were evaluated. Powder X-ray diffraction was used to investigate the purity, crystal structure, and size of the NPs, and the average size of the NPs was determined to be ∼ 25 nm. The internal surface morphology of the NPs with distinct voids and pores were observed using scanning electron microscopy (SEM) Ultraviolet–visible (UV-vis) absorption spectroscopy was used to analyze the optical properties of the as-synthesized ZrO₂ NPs, and their energy bandgap was determined to be 4.5 eV. The photoluminescence (PL) spectrum of the cubic-phase ZrO₂ NPs presented a broad band in the UV-vis region. The PL emission properties of the ZrO₂ NPs were studied by analyzing their emission wavelength at ∼490 nm, and the results revealed that the NPs can be efficiently used for display applications. The electrochemical properties of a graphite–ZrO₂ NP electrode was qualitatively analyzed by performing cyclic voltammetry (CV) and electrochemical impedance spectroscopy experiments in a three–electrode system with a 0.1 M KCl solution as the electrolyte. Our results suggested that the NPs can be used to evaluate the thermodynamics of the redox reaction, and their capacitance was determined using the CV curves of a graphite–ZrO₂ working electrode at different scan rates in the range of 0.01 ∼ 0.05 V/s at room temperature. Furthermore, the photodegradation rate of Reactive Blue 4 textile dye over the as-prepared ZrO₂ NPs reached 97% under UV-vis light irradiation.

Non-noble transition metal oxides (TMOs) are promising catalysts with improved catalytic activity and stability in oxygen evolution reaction (OER). However, the structural complexity of TMO-based electrocatalysts renders the determination of the active sites and OER mechanisms challenging. Here, we demonstrate that the OER activity of Co-doped one-dimensional W₁₈O₄₉ (Co-W₁₈O₄₉) is intrinsically dominated by the surface structure and electronic properties of the octahedral sites and Co–O–W bonds. Compared with RuO₂ and W₁₈O₄₉ heterogeneous electrocatalysts, Co-W₁₈O₄₉ exhibits higher turnover frequency, attaining 1.97 s⁻¹ at 500 mV overpotential. The results indicate that Co substitution contributes to the localized charge distribution of the active octahedral sites constructed by the Co–O–W bonds under OER conditions. Here, we determine the mechanism of TMOs for the OER, which may be applied to various other TMOs for OER electrocatalyst design.

Micro/nanomotors (MNMs) are small-scale devices that can effectively convert various forms of energy into mechanical motion. Their controllable motility and good permeability have attracted the interest of researchers as promising drug carriers in cancer therapy. Compared with traditional formulations, micro/nanomotor drug delivery systems can greatly improve therapeutic efficiency and reduce the side effects of antitumor drugs. This review mainly discusses the advantages of micro/nanomotor drug delivery systems and the applications of MNMs propelled by exogenous, endogenous, and biohybrid power in cancer therapy. Finally, the main challenges of the applications of micro/nanomotor drug delivery systems, as well as future development trends and opportunities are discussed.