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Metallic iron (Fe) typically demonstrates the unfavorable catalytic activity for the CO 2 reduction reaction (CO 2 RR), mainly attributed to the excessively strong binding of CO products on Fe sites. Toward this end, we employed an effective approach involving electronic structure modulation through nitrogen (N) integration to enhance the performance of the CO 2 RR. Here, an efficient catalyst has been developed, composed of N-doped metallic iron (Fe) nanoparticles encapsulated in a porous N-doped carbon framework. Notably, this N-integrated Fe catalyst displays significantly enhanced performance in the electrocatalytic reduction of CO 2 , yielding the highest CO Faradaic efficiency of 97.5% with a current density of 6.68 mA cm -2 at -0.7 V versus the reversible hydrogen electrode. The theoretical calculations, combined with the in situ attenuated total reflection surface-enhanced infrared absorption spectroscopy study, reveal that N integration modulates the electron density around Fe, resulting in the weakening of the binding strength between the Fe active sites and *CO intermediates, consequently promoting the desorption of CO and the overall CO 2 RR process.

The electroreduction of carbon dioxide (CO 2 ) to a liquid product is a viable method for establishing an artificial carbon cycle. Unfortunately, most electrocatalysts' low efficiency and instability prevent them from being used in practical applications. In the current study, we developed ultrasmall Cu nanocrystals embedded in nitrogen-doped carbon nanosheets (Cu/NC-NSs) for selective CO 2 electroreduction by adjusting the potential. Cu/NC-NSs had 43.7 and 63.5% Faradaic efficiencies for the synthesis of ethanol and formate with applied potentials of -0.37 and -0.77 V vs reversible hydrogen electrode (RHE) using a flow cell architecture, respectively. Moreover, these Cu/NC-NSs show a steady catalytic performance up to 16 h. Density functional theory (DFT) calculations were performed to investigate the reaction mechanism. Furthermore, the synergistic effect formed by nitrogen-doped carbon and highly dispersed copper atoms led to their excellent performance in CO 2 electroreduction.

Precise control over the interlayer spacing for K + intercalation is an effective approach to boost the potassium-storage performances in carbonaceous materials. Herein, we first found that the optimal interlayer spacing for K + intercalation is around 0.38 nm for N, O codoped carbon nanofibers (NOCNs), displaying a reversible capacity of 627 mAh g -1 at 0.1 A g -1 after 200 cycles, excellent rate capability (123 mAh g -1 at 20 A g -1 ), and ultrastable cycling stability (262 mAh g -1 at 5 A g -1 after 10 000 cycles). Such good potassium-storage performances have never been reported in carbonaceous materials. The theoretical calculations and electrochemical studies reveal that the optimal interlayer spacing and N, O heteroatom-induced active sites work together to provide an intercalation-adsorption mechanism for storing K + in carbonaceous materials. This work facilitates the understanding of the role of the critical interlayer spacing for K + intercalation in carbonaceous materials.

Potassium ion batteries (KIBs) have attracted great attention recently as a promising large-scale energy storage system by virtue of the bountiful K resource and low standard hydrogen potential of K + /K. However, their development is hindered by the limited capacity and inferior cycling stability resulting from the large size of K + . Here, a unique vanadium sulfide@carbon nanorod is designed and synthesized for high-performance KIBs. Thanks to the hybrid structure, abundant active sites, fast ion diffusion, and capacitive-like electrochemical behavior of the electrode, the anode exhibits a large specific capacity (468 mA h g -1 after 100 cycles at 0.1 A g -1 ), predominant rate performance (205 mA h g -1 at 5 A g -1 ), and impressive cycling stability (171 mA h g -1 for 4000 cycles at 3 A g -1 ). Furthermore, the constructed KIB full cell demonstrates 229 mA h g -1 at 0.5 A g -1 and 86% capacity retention over 300 cycles.

Metal phosphides with a high theoretical capacity and low redox potential have been proposed as promising anodes for potassium-ion batteries (PIBs). A reasonable configuration design and introduction of a hollow structure with adequate internal void spaces are effective strategies to overcome the volume expansion of metal phosphides in potassium-ion batteries. Herein, we report a cage-confinement pyrolysis strategy to obtain hollow nanocage-structured nitrogen/phosphorus dual-doped carbon-coated copper phosphide (Cu 3 P/CuP 2 @NPC), which exhibits a high initial charge capacity (409 mA h g -1 at 100 mA g -1 ) and an outstanding cycle performance (100 mA h g -1 after 5000 cycles at 1000 mA g -1 ) as an anode material for PIBs. The novel hollow nanocage structure could prevent volume expansion during cycling and reduce the electron/ion diffusion distance. Besides, the nitrogen/phosphorus dual-doped carbon-coated layer could promote electronic conductivity. In situ X-ray diffraction (XRD) measurements are conducted to study the potassiation/depotassiation mechanism of Cu 3 P/CuP 2 @NPC and reveal the structure stability during the cycle process, which further proves that the design ideas of the conductive carbon layer and the hollow structure with adequate internal void spaces are successful.

Artemisinin compounds have shown satisfactory safety records in anti-malarial clinical practice over decades and have revealed value as inexpensive anti-tumor adjuvant chemotherapeutic drugs. However, the rational design and precise preparation of nanomedicines based on the artemisinin drugs are still limited due to their non-aromatic and fragile chemical structure. Herein, a bioinspired coordination-driven self-assembly strategy was developed to manufacture the artemisinin-based nanoprodrug with a significantly increased drug loading efficacy (∼70 wt %) and decreased preparation complexity compared to conventional nanodrugs. The nanoprodrug has suitable size distribution and robust colloidal stability for cancer targeting in vivo . The nanoprodrug was able to quickly disassemble in the tumor microenvironment with weak acidity and a high glutathione concentration, which guarantees a better tumor inhibitory effect than direct administration and fewer side effects on normal tissues in vivo . This work highlights a new strategy to harness a robust, simplified, organic solvent-free, and highly repeatable route for nanoprodrug manufacturing, which may offer opportunities to develop cost-effective, safe, and clinically available nanomedicines.

Preferential oxidation (PROX) of CO in hydrogen is of great significance for proton exchange membrane fuel cells (PEMFCs) that need a CO-free hydrogen stream as fuel. The key technical problem is developing catalysts that can efficiently remove CO from the H 2 -rich stream within the working temperature range of PEMFCs. Herein, we design a Au/Bi 2 O 3 interfacial catalyst for PROX with excellent catalytic performance, which can achieve 100% CO conversion in the PROX reaction over a wide temperature window (70-200 °C) and is perfectly compatible with the operating temperature window (80-180 °C) of PEMFCs. Moreover, the catalyst also demonstrates excellent high flow performance and long-term stability. Density functional theory (DFT) calculations reveal that the electrons transferring from Bi 2 O 3 to Au and then to adsorbed perimeter CO and O 2 molecules promote the activation of CO and O 2 , thus enhancing the catalytic performance of PROX.

Safe storage and transportation of H 2 is a fundamental requirement for its wide applications in the future. Controllable release of high-purity H 2 from a stable storage medium such as CH 3 OH before use offers an efficient way of achieving this purpose. In our case, Cu nanoclusters uniformly dispersed onto (001) surfaces of TiO 2 nanosheets (TiO 2 /Cu) are selectively prepared by thermal treatment of HKUST-1 loaded TiO 2 nanosheets. One of the TiO 2 /Cu composites, TiO 2 /Cu_50, exhibits remarkably high activity toward the selective dehydrogenation of CH 3 OH to HCHO with a H 2 evolution rate of 17.8 mmol h -1 per gram of catalyst within a 16-h photocatalytic reaction (quantum efficiency at 365 nm: 16.4%). Theoretical calculations reveal that interactions of Cu nanoclusters with TiO 2 could affect their electronic structures, leading to higher adsorption energy of CH 3 OH at Ti sites and a lower barrier for the dehydrogenation of CH 3 OH by the synergistic effect of Cu nanoclusters and TiO 2 , and lower Gibbs free energy for desorption HCHO and H 2 as well.

Effective control of the molecular orientation and the degree of ordering in organic semiconductors is important to achieve high-performance organic electronics. Herein, we have successfully achieved highly oriented films in centimeter scale for a naphthalenedicarboximide-based semiconducting polymer (P(NDI2OD-T2)) by solvent vapor annealing (SVA) of precast films under a high magnetic field (HMF). As revealed by the microstructural studies, the SVA-HMF films exhibit a remarkably higher degree of chain alignment and high morphological uniformity compared to the HMF-guided drop-cast films. Based on the structural evolution of the films with the SVA time, a mechanism is proposed to elucidate the alignment process, which emphasizes that the chain aggregates re-formed in the swollen films trigger magnetic alignment and determine the film order. Compared with the unaligned films, field-effect transistors of the magnetic aligned P(NDI2OD-T2) films have exhibited a 19-fold enhancement of electron mobility and an extraordinarily large mobility anisotropy of 125. Furthermore, a significantly reduced energetic barrier for activated transport is observed on the aligned devices from temperature-variable measurements. The improved performance achieved by the HMF-SVA process has indicated its potential for high-performance organic electronic applications.

A novel design of no-loading and bifunctional positive electrode, serving as an active material and current collector simultaneously, has been constructed by grass-like nickel foam which shows a battery-type performance and excellent areal specific capacity at 0.540 mA h·cm -2 (over 4500 mF·cm -2 ). To obtain a high-performance hybrid capacitor, layered porous carbonaceous composites C/MgO negative electrodes were fabricated, in which MgO nanoparticles serve as "reservoirs" for OH - ions from the electrolyte. Compared with other carbon materials, such as carbon fibers, hollow nanospheres, and nanotubes, the three-dimensional (3D) hierarchical heterostructures of the C/MgO electrode exhibit a higher storage performance of 424.1 mF·cm -2 . Assembled by these two working electrodes, a hybrid capacitor with uncommon galvanostatic charge/discharge cycling curve has been well-investigated in an alkaline aqueous electrolyte system. This as-coupled hybrid capacitor exhibits an engaging activation process during multiple cycling tests and leads to a drastically improved energy density of 60% (from 80.4 to 128.8 μW h·cm -2 ), which can be attributed to a "match behavior" between its positive and negative electrodes.

Phothermal therapy has received increasing attention in recent years as a potentially effective way to treat cancer. In pursuit of a more biocompatible photothermal agent, we utilize biosafe materials including ellagic acid (EA), polyvinylpyrrolidone (PVP), and iron element as building blocks, and we successfully fabricate a homogeneous nanosized Fe-EA framework for the first time by a facile method. As expected, the novel nanoagent exhibits no obvious cytotoxicity and good hemocompatibility in vitro and in vivo. The microenvironment responsiveness to both pH and hydrogen peroxide makes the NPs biodegradable in tumor tissues, and the framework should be easily cleared by the body. Photothermal potentials of the nanoparticles are demonstrated with relevant features of strong NIR light absorption, moderately effective photothermal conversion efficiency, and good photothermal stability. The in vivo photothermal therapy also achieved effective tumor ablation with no apparent toxicity. On the other hand, it also exhibits T2 MR imaging ability originated from ferric ions. Our work highlights the promise of the Fe-EA framework for imaging-guided photothermal therapy.

A new surface modification method is developed for electroless deposition of robust metal (copper, nickel, silver) layers on poly(dimethylsiloxane) (PDMS) substrate with strong adhesion. Under the synergies of the polydopamine (PDA), the plasma process enhances Ag + reduction, and a thin Ag film is capable of tightly attaching to the PDMS surface, which catalyzes electroless deposition (ELD) to form robust metal layers on the PDMS surface with strong adhesion. Subsequently, a flexible and stretchable Cu-PDMS conductor is obtained through this method, showing excellent metallic conductivity of 1.2 × 10 7 S m -1 , even at the longest stretch strain (700%). This process provides a successful strategy for obtaining good robust metal layers on PDMS and other polymer substrate surfaces with strong adhesion and conductivity.

The catalytic performance of Pd-based catalysts has long been hindered by surface contamination, particle agglomeration, and lack of rational structural design. Here we report a simple adsorption method for rapid synthesis (∼90 s) of structure-optimized Pd alloy supported on nitrogen-doped carbon without the use of surfactants or extra reducing agents. The material shows much lower overpotential than 30 wt % Pd/C and 40 wt % Pt/C catalysts while exhibiting excellent durability (80 h). Moreover, unveiled by the density functional theory (DFT) calculation results, the underlying reason for the outstanding performance is that the PdMnCo alloy/pyridinic nitrogen-doped carbon interfaces weaken the hydrogen-adsorption energy on the catalyst and thus optimize the Gibbs free energy of the intermediate state (ΔG H* ), leading to a remarkable electrocatalytic activity. This work also opens up an avenue for quick synthesis of a highly efficient structure-optimized Pd-based catalyst.

Designing and exploring catalysts with high activity and stability for oxygen reduction reaction (ORR) at the cathode in acidic environments is imperative for the industrialization of proton exchange membrane fuel cells (PEMFCs). Theoretical calculations and experiments have demonstrated that alloying Pt with a transition metal can not only cut down the usage of scarce Pt metal but also improve performance of mass activity compared with pure Pt. Herein, we exhibit the preparation of nanoporous PtFe nanoparticles (np-PtFe NPs) supported on N-doped porous carbon sheets (NPCS) via facile in situ thermolysis of a Pt-modified Fe-based metal-organic framework (MOF). The np-PtFe/NPCS exhibit a more positive half-wave potential (0.92 V) compared with commercial Pt/C catalyst (0.883 V). The nanoporous structure allows our catalyst to possess high mass activity, which is found to be 0.533 A·mg Pt -1 and 3.04 times better than that of Pt/C (0.175 A·mg Pt -1 ). Moreover, the conversion of PtFe NPs from porous to hollow structure can maintain the activity of electrocatalyst. Our strategy provides a facile design and synthesis process of noble-transition metal alloy electrocatalysts via noble metal modified MOFs as precursors.

Multifunctional nanocarriers with good biocompatibility, good imaging function, and smart drug delivery ability are crucial for realizing highly efficient imaging-guided chemotherapy in vivo. This paper reports a type of chitosan-carbon dot (CD) hybrid nanogels (CCHNs, ∼65 nm) by integrating pH-sensitive chitosan and fluorescent CDs into a single nanostructure for simultaneous near-infrared (NIR) imaging and NIR/pH dual-responsive drug release to improve therapeutic efficacy. Such CCHNs were synthesized via a nonsolvent-induced colloidal nanoparticle formation of chitosan-CD complexes assisted by ethylenediaminetetraacetic acid (EDTA) molecules in the aqueous phase. The selective cross-linking of chitosan chains in the nanoparticles can immobilize small CDs complexed in the chitosan networks. The resultant CCHNs display high colloidal stability, high loading capacity for doxorubicin (DOX), bright and stable fluorescence from UV to NIR wavelength range, efficient NIR photothermal conversion, and intelligent drug release in response to both NIR light and change in pH. The results from in vitro tests on cell model and in vivo tests on different tissues of animal model indicate that the CCHNs are nontoxic. The DOX-loaded CCHNs can permeate into the implanted tumor on mice and release drug molecules efficiently on site to inhibit tumor growth. The additional photothermal treatments from NIR irradiation can further inhibit the tumor growth, benefited from the effective NIR photothermal conversion of CCHNs. The demonstrated CCHNs manifest a great promise toward multifunctional intelligent nanoplatform for highly efficient imaging-guided cancer therapy with low side effects.

The hydrogen evolution reaction highly relied on Pt electrocatalysts, with high activity and stability. In the past few years, a host of efforts have been made in the development of novel platinum nanostructures with a low amount of Pt because the scarcity and high price of Pt hinder its practical applications. Here, we report the preparation of PtCoFe@CN electrocatalysts with a remarkably reduced Pt loading amount of 4.60% by annealing Pt-doped metal-organic frameworks (MOFs). The electrocatalyst demonstrated an outstanding performance with only 45 mV overpotential to achieve the 10 mA cm -2 current density, which is quite close to that of the commercial 20% Pt/C catalyst. The enhanced catalytic capability is originated from the modification of the electronic structures of CoFe by alloying with Pt. The results indicate that robust and superstable alloy electrocatalysts which contain a very small amount of noble metal could be prepared by annealing noble metal-doped MOFs.

The water electrolysis is of critical importance for sustainable hydrogen production. In this work, a highly efficient and stable PdCo alloy catalyst (PdCo@CN) was synthesized by direct annealing of Pd-doped metal-organic frameworks (MOFs) under N2 atmosphere. In 0.5 M H2SO4 solution, PdCo@CN displays remarkable electrocatalytic performance with overpotential of 80 mV, a Tafel slope of 31 mV dec(-1), and excellent stability of 10 000 cycles. Our studies reveal that noble metal doped MOFs are ideal precursors for preparing highly active alloy electrocatalysts with low content of noble metal.

Nanocatalysts have very high catalytic activities due to surface atoms with their unpaired spins. It is the purpose of this paper to investigate the effect of magnetic fields (MFs) on the arrangement of surface spins and their catalytic activities. Pd nanoparticles supported on MIL-100(Cr) were selected as catalysts for the reduction of 4-nitrophenol under MFs. The result demonstrates that MFs can reduce the reaction time from 2.6 to 1.4 min under 0.5 T. This study first shows that the configuration of surface spins has an effect on the catalytic activity, which can be regulated by a foreign MF.

Coordination polymers with large surface areas and uniform but tunable cavities have attracted extensive attention because of their unique properties and potential applications in numerous fields. The introduction of noble metal into coordination polymers, which may enhance or display new behaviors beyond their parent counterparts, presents great challenges in maintaining the fragile coordination structures and meeting the compatibility. Here, cyano-bridged coordination polymers are robust and show very nice compatibilities with a series of noble metals, such as Pd, Pt, Au, Ag. Those noble elements partially take the place of the transition metal ions under room temperature (for Au and Ag) or a mild hydrothermal environment (for Pd and Pt) without damaging the framework. By using this universal simple synthetic procedure, we prepared a series of noble metal containing metal hexacyanoferrate (MHCF) with various morphologies and structures, including Pd/Pt/Ag/Au-MnHCF, Pd/Pt/Ag/Au-CoHCF, and Pd/Pt/Ag/Au-NiHCF. Among them, Pd-MnHCF demonstrates the control of morphologies by adjusting operational details, and notably, it shows very unique, enhanced catalytic performance, reflecting the superiority of cyano-connected positive-valent Pd as a single-atom catalyst.

Herein, we report a novel and facile route for the large-scale fabrication of 2D porous NixCo3-xO4 nanosheets, which involves the thermal decomposition of NixCo1-x hydroxide precursor at 450 °C in air for 2 h. The as-prepared 2D porous NixCo3-xO4 nanosheets exhibit an enhanced lithium storage capacity and excellent cycling stability (1330 mA h g(-1) at a current density of 100 mA g(-1) after 50 cycles). More importantly, it can render reversible capacity of 844 mA h g(-1), even at a high current density of 500 mA g(-1) after 200 cycles, indicating its potential applications for high power LIBs. Compared to pure Co3O4, the reduction of Co in NixCo3-xO4 is of more significance because of the high cost and toxicity of Co. The improved electrochemical performance is attributed to the 2D structure and large amounts of mesopores within the nanosheets, which can effectively improve structural stability, reduce the diffusion length for lithium ions and electrons, and buffer volume expansion during the Li(+) insertion/extraction processes.

A facile two-step synthesis method has been developed for the synthesis of highly active and well-defined Pt-Pd nanoalloys supported on the surface of Fe3O4@C colloidal nanoparticles. The nanoalloys were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), scanning transmission electron microscopy (STEM) with line scanning of energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy. The nanoalloys exhibit remarkable catalytic activity toward reduction of 4-nitrophenol to 4-aminophenol by NaBH4. Furthermore, the catalytic activity of the supported nanoalloys could be further optimized by tuning the composition of the supported nanoalloys, and the optimized catalytic activity is obtained with a normalized rate constant of about 12.03 nmol(-1) s(-1) when the atomic ratio of Pd to Pt is tuned to 2.07:1, which is advancing among the Pd-based nanocatalysts reported in the recent years.

The separation and reuse of nanocatalysts remains a major challenge. Herein, we report a novel approach to prepare palladium nanowire array catalysts by reducting PdCl2 in the pores of anodic aluminum oxide (AAO) templates with backside Al sheets via a hydrothermal process. Suzuki coupling reactions and 4-nitrophenol (4-NP) reduction reactions were employed to study the catalytic activity of the nanocatalysts. The nanocatalysts demonstrated good activity, great thermal stability, easy separation, and excellent reusability in both Suzuki reaction and 4-NP reduction.