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Developing highly active and selective catalysts for the hydrogenation of nitroarenes, an environmentally benign process to produce industrially important aniline intermediates, is highly desirable...

Single-atom catalysts (SACs), featuring high atom utilization, have captured widespread interests in diverse applications. However, the single-atom sites in SACs are generally recognized as independent units and the interplay of adjacent sites is largely overlooked. Herein, by the direct pyrolysis of MOFs assembled with Fe and Ni-doped ZnO nanoparticles, a novel Fe1-Ni1-N-C catalyst, with neighboring Fe and Ni single-atom pairs decorated on nitrogen-doped carbon support, has been precisely constructed. Thanks to the synergism of neighboring Fe and Ni single-atom pairs, Fe1-Ni1-N-C presents significantly boosted performances for electrocatalytic reduction of CO2, far surpassing Fe1-N-C and Ni1-N-C with separate Fe or Ni single atoms. Additionally, the Fe1-Ni1-N-C also exhibits superior performance with excellent CO selectivity and durability in Zn-CO2 battery. Theoretical simulations reveal that, in Fe1-Ni1-N-C, single Fe atoms can be highly activated by adjacent single-atom Ni via non-bonding interaction, significantly facilitating the formation of COOH* intermediate and thereby accelerating the overall CO2 reduction. This work supplies a general strategy to construct single-atom catalysts containing multiple metal species and reveals the vital importance of the communitive effect between adjacent single atoms toward improved catalysis.

Two-dimensional (2D) IV–VI nanomaterials have been important candidates for energy conversion and storage. However, there is still lack of a simple method of realizing control synthesis of IV–VI na...

The kinetics of electrode reactions including mass transfer and surface reaction is essential in electrocatalysis, as it strongly determines the apparent reaction rates, especially on nanostructured electrocatalysts. However, important challenges still remain in optimizing the kinetics of given catalysts with suitable constituents, morphology, and crystalline design to maximize the electrocatalytic performances. We propose a comprehensive kinetic model coupling mass transfer and surface reaction on the nanocatalyst-modified electrode surface to explore and shed light on the kinetic optimization in electrocatalysis. Moreover, a theory-guided microchemical engineering (MCE) strategy has been demonstrated to rationally redesign the catalysts with optimized kinetics. Experimental measurements for methanol oxidation reaction in a 3D ordered channel with tunable channel sizes confirm the calculation prediction. Under the optimized channel size, mass transfer and surface reaction in the channeled microreactor are both well regulated. This MCE strategy will bring about a significant leap forward in structured catalyst design and kinetic modulation.

Energy is an important substantial foundation for the survival and development of humans. However, the over-consumption of resources and environmental pollution have become more prominent. The key factors for solving energy problems are to increase energy utilization efficiency and optimize energy structure. The development of new materials is the research emphasis in the field of material chemistry all the time. For instance, developing new light-capture materials and catalysts to improve the efficiency of existing photovoltaic cells is one of the most effective approaches to increasing solar power capacity radically. The design of high-performance catalytic materials to make better use of energy from fossil fuels and biomass. In addition, it is an important research direction of material chemistry and energy chemistry to deeply understand the reaction mechanism of energy conversion.

Introducing heating function to oil sorbents opens up a new pathway to the fast cleanup of viscous crude oil spills in situ. The oil sorption speed increases with the rise of the temperature, thus oil sorbents with high heating temperature are desirable. Besides, the oil sorbents also need to be produced environment-friendly. Here we present carbonized melamine-formaldehyde sponges (CMSs) that exhibited superior heating performance and the CMSs could be massively fabricated through a non-polluting pyrolysis process. The conductive CMSs could be heated over 300 °C with a low applied voltage of 6.9 V and keep above 250 °C for 30 min in the air without obvious damage. Such high heating performance enabled heating up the oil spills with a high rate of 2.65 °C·s−1 and 14% improvement of oil sorption coefficient compared with the state-of-the-art value. We demonstrated that one joule-heated CMS could continuously and selectively collect viscous oil spills (9,010 mPa·s) 690 times its own weight in one hour. The CMSs will be a highly competitive sorbent material for the fast remediation of future crude oil spills.

Siloxane rubber shows attractive properties of high stability, elasticity and transparency. Besides, the regulation of its properties renders it widely used in many application fields. However, most of the reported performance improvement methods of siloxane rubber focus on the change of chemical composition of siloxane rubber, including the design of molecular chain and the introduction of other compounds, etc. Such a strategy is still faced with many limitations in practical application. In this work, on the premise of not changing the chemical composition of siloxane rubber, we propose a facile solvothermal polymerization process to change the structure of cross-linking networks, so as to obtain the siloxane rubber with controllable mechanical properties. Compared to the normal curing method, we realized polydimethylsiloxane elastomer (PDMS) with maximum elongation of more than 3,000% (> 10 times of normally cured one) and tensile modulus lower than 0.15 MPa (< 1/10 of normally cured one). In addition to superior stretchability, it gains extra high softness, stickiness and sensitive response to organic solvents. Based on our solvothermal cured PDMS, its applications in oil collection and organic solvent sensor have been demonstrated. It is expected that this method can be readily utilized widely and shows great application potentials.

Summary Creating free-access active sites and regulating their interaction with substrates are crucial for efficient catalysis, yet remain a grand challenge. Herein, naked Pd nanoparticles (NPs) have been encapsulated in a metal-organic framework (MOF), MIL-101-NH2, to afford Pd@MIL-101-NH2. The hydrophobic perfluoroalkyls were post-synthetically modified onto -NH2 group to yield Pd@MIL-101-Fx (x = 3, 5, 7, 11, 15), which engineer the MOF pore walls to regulate Pd surrounding microenvironment and interaction with substrates. As a result, both the dehydrogenation coupling of organosilane and hydrogenation of halogenated nitrobenzenes show that their activity and selectivity can be greatly promoted upon hydrophobic modification due to the favorable substrate enrichment and regulated interactions between Pd and the modified MOF hosts, far surpassing the traditional supported or surfactant-protected Pd NPs. We envision metal NPs@MOF composites would be an ideal platform integrating the inherent activity of well-accessible metal sites with engineered microenvironment via readily tunable MOFs.

Biomimetic nacrelike designs not only present a rational strategy for preparing robust materials but also open the avenue for regulating nanofluidic ion transport.

Suppressing the polysulfide shuttle effect and promoting the conductivity of electrode materials have become efficient ways to achieve high cycling stability for Li–S batteries. However, this still remains a challenge. New multicore closely packed ultrathin-MnO2@N-doped carbon-gear yolk–shell micro-nanostructures are explored as the S host material to trap polysulfides and enhance conductivity. Such composites can accommodate S mass-loading up to 80 wt% via a valid sulfur solution infiltration approach. The cooperation of ultrathin-MnO2 yolks with N-doped carbon internal gear shells can well suppress the polysulfide shuttle effect by strong chemical interactions and physical confinement as well as enhanced conductivity for excellent Li–S battery properties, which enable an initial gravimetric capacity of 1245 mA h g−1 and a low decay rate of 0.03% per cycle over 1000 cycles at 1C. In particular, the composite delivers an initial gravimetric capacity of 1097.8 mA h g−1 and volumetric capacity of 1059.6 mA h cm−3 at 2C rate. Specifically, the electrochemical performance of the designed composite at different electrolyte/S ratios is firstly investigated in this study, and is a promising approach with the high-performance cathode material for Li–S batteries.

Undoubtedly humidity is a non-negligible and sensitive problem for cellulose, which is usually regarded as one disadvantage to cellulose-based materials because of the uncontrolled deformation and mechanical decline. But the lack of an in-depth understanding of the interfacial behavior of nanocellulose in particular makes it challenging to maintain anticipated performance for cellulose-based materials under varied relative humidity (RH). Starting from multiscale mechanics, we herein carry out first-principles calculations and large-scale molecular dynamics simulations to demonstrate the humidity-mediated interface in hierarchical cellulose nanocrystals (CNCs) and associated deformation modes. More intriguingly, the simulations and subsequent experiments reveal that water molecules (moisture) as the interfacial media can strengthen and toughen nanocellulose simultaneously within a suitable range of RH. From the perspective of interfacial design in materials, the anomalous mechanical behavior of nanocellulose with humidity-mediated interfaces indicates that flexible hydrogen bonds (HBs) play a pivotal role in the interfacial sliding. The difference between CNC-CNC HBs and CNC-water-CNC HBs triggers the humidity-mediated interfacial slipping in nanocellulose, resulting in the arising of a pronounced strain hardening stage and the suppression of strain localization during uniaxial tension. This inelastic deformation of nanocellulose with humidity-mediated interfaces is similar to the Velcro-like behavior of a wet wood cell wall. Our investigations give evidence that the humidity-mediated interface can promote the mechanical enhancement of nanocellulose, which would provide a promising strategy for the bottom-up design of cellulose-based materials with tailored mechanical properties.

Lightweight yet strong paper with high toughness is desirable especially for impact protection. Herein we demonstrated electrically conductive and mechanically robust paper (AP/PB-GP) made of reduced graphene oxide via interfacial crosslinking with 1-aminopyrene (AP) and 1-pyrenebutyrat (PB) small molecules. The AP/PB-GP with thickness of over ten micrometer delivers a record-high toughness (∼69.67 ± 15.3 MJ m−3 in average), simultaneously with superior strength (close to 1 GPa), allowing an impressive specific penetration energy absorption (∼0.17 MJ kg−1) at high impact velocities when used for ballistic impact protection. Detailed interfacial and structural analysis reveals that the reinforcement is synergistically determined by π-π interaction and H-bonding linkage between adjacent graphene lamellae. Especially, the defective pores within the graphene platelets benefit the favorable adsorption of the pyrene-containing molecules, which imperatively maximizes the interfacial binding, facilitating deflecting crack and plastic deformation under loading. Density functional theory simulation suggests that the coupling between the polar functional groups, e.g., −COOH, at the edges of graphene platelets and −NH2 and −COOH of AP/PB are critical to the formation of hydrogen bonding network.

Magnesium calcite (Mg-calcite) mesocrystal is widespread in the biominerals with specific functions. Until now, it remains challenging to obtain Mg-calcite mesocrystals without organic additives and the formation mechanism of Mg-calcite mesocrystals in the ocean is not clear yet. We report here the synthesis of corn-like Mg-calcite mesocrystals from pure amorphous calcium carbonate (ACC) via a facile method only by using Ca2+ and Mg2+. The obtained Mg-calcite is composed of many nanocubes with common crystallographic orientation, which shows very good single crystal feature. In the crystallizing procedure, the ACC nanospheres rapidly agglomerate into Mg-calcite corn-like mesocrystal by oriented attachment (OA) in a certain direction, which belongs to the non-classical nucleation. By this method, the molar ratio of Ca2+ and Mg2+ plays a vital role in the whole crystallization procedure, which may shed a new light on disclosing the mechanism behind for the effect of seawater in the formation of biological Mg-calcite in nature.

Petroleum-based plastics are useful but they pose a great threat to the environment and human health. It is highly desirable yet challenging to develop sustainable structural materials with excellent mechanical and thermal properties for plastic replacement. Here, inspired by nacre’s multiscale architecture, we report a simple and efficient so called “directional deforming assembly” method to manufacture high-performance structural materials with a unique combination of high strength (281 MPa), high toughness (11.5 MPa m1/2), high stiffness (20 GPa), low coefficient of thermal expansion (7 × 10−6 K−1) and good thermal stability. Based on all-natural raw materials (cellulose nanofiber and mica microplatelet), the bioinspired structural material possesses better mechanical and thermal properties than petroleum-based plastics, making it a high-performance and eco-friendly alternative structural material to substitute plastics., It is desirable yet challenging to develop sustainable structural materials to replace petroleum-based plastics. Here, the authors report a facile assembly method for manufacturing high-performance structural materials with a unique combination of high strength, toughness and stiffness.

Although solar-driven water splitting on semiconductor photocatalysts is an attractive route for hydrogen generation, there is a lack of excellent photocatalysts with high visible light activity. Due to their tunable bandgaps suitable for superior visible-light absorption, copper-based quaternary sulfides have been the important candidates. Here, we first assessed the preferred facet of wurtzite Cu-Zn-In-S for photocatalytic hydrogen evolution reaction using the relevant Gibbs free energies determined by first principle calculation. We then developed a colloidal method to synthesize single crystalline wurtzite Cu-Zn-In-S nanobelts (NBs) exposing (0001) facet with the lowest reaction Gibbs energy, as well as Cu-Zn-Ga-S NBs exposing (0001) facet. The obtained single crystalline Cu-Zn-In-S and Cu-Zn-Ga-S NBs exhibit superior hydrogen production activities under visible-light irradiation, which is composition-dependent. Our protocol represents an alternative surface engineering approach to realize efficient solar-to-chemical conversion of single crystalline copper-based multinary chalcogenides., Quaternary sulfides are important candidates for solar-to-H2 conversion due to tunable bandgaps for controllable light absorption. Here, authors prepare single crystalline wurtzite Cu-Zn-In-S and Cu-Zn-Ga-S nanobelts with (0001) facets that show strong photocatalytic H2 production performances.

Summary Plastics play a critical role in daily life but possess a considerably increasing negative impact on the environment and human health. Fabrication of biodegradable and eco-friendly alternatives with competitive properties for plastic substitute is urgently needed. Here, inspired by the hierarchical structure of nacre, we firstly developed a high-performance nacre-inspired composite with high transmittance (83.4% at 550 nm) and high haze (88.8% at 550 nm) via an aerosol-assisted biosynthesis process combined with the hot-press technique. The nacre-inspired composite film combines higher strength (482 MPa) and toughness (17.71 MJ m−3) than most other nacre-inspired films, and can be folded into various shapes without visible failure after unfolding. Moreover, compared with most commercial plastic films, it exhibits a lower thermal expansion coefficient (∼3 ppm K−1) and higher maximum service temperature besides better mechanical properties, which makes it a promising alternative to plastics in many technical fields.

Single-atom catalysts (SACs) are of great interest because of their ultrahigh activity and selectivity. However, it is difficult to construct model SACs according to a general synthetic method, and therefore, discerning differences in activity of diverse single-atom catalysts is not straightforward. Herein, a general strategy for synthesis of single-atom metals implanted in N-doped carbon (M1 -N-C; M=Fe, Co, Ni and Cu) has been developed starting from multivariate metal-organic frameworks (MOFs). The M1 -N-C catalysts, featuring identical chemical environments and supports, provided an ideal platform for differentiating the activity of single-atom metal species. When employed in electrocatalytic CO2 reduction, Ni1 -N-C exhibited a very high CO Faradaic efficiency (FE) up to 96.8 % that far surpassed Fe1 -, Co1 - and Cu1 -N-C. Remarkably, the best-performer, Ni1 -N-C, even demonstrated excellent CO FE at low CO2 pressures, thereby representing a promising opportunity for the direct use of dilute CO2 feedstock.

Although nickel-based catalysts display good catalytic capability and excellent corrosion resistance under alkaline electrolytes for water splitting, it is still imperative to enhance their activity for real device applications. Herein, we decorated Ni0.85Se hollow nanospheres onto reduced graphene oxide (RGO) through a hydrothermal route, then annealed this composite at different temperatures (400 °C, NiSe2-400 and 450 °C, NiSe2-450) under argon atmosphere, yielding a kind of NiSe2/RGO composite catalysts. Positron annihilation spectra revealed two types of vacancies formed in this composite catalyst. We found that the NiSe2-400 catalyst with dual Ni-Se vacancies is able to catalyze the oxygen evolution reaction (OER) efficiently, needing a mere 241 mV overpotential at 10 mA·cm−2. In addition, this catalyst exhibits outstanding stability. Computational studies show favorable energy barrier on NiSe2-400, enabling moderate OH− adsorption and O2 desorption, which leads to the enhanced energetics for OER.

Printable elastic conductors promote the wide application of consumable electronic textiles (e-textiles) for pervasive healthcare monitoring and wearable computation. To assure a clean appearance, the e-textiles require a washing process to clean up the dirt after daily use. Thus, it is crucial to develop low-cost printable elastic conductors with strong adhesion to the textiles. Here, we report a composite elastic conductor based on Ag nanowires (NWs) and polyurethane elastomer. The composite could be dispersed into ink and easily printed onto textiles. One-step print could form robust conductive coatings without sealing on the textiles. Interestingly, the regional concentration of Ag NWs within the polyurethane matrix was observed during phase inversion, endowing the elastic conductor with a low percolation threshold of 0.12 vol.% and high conductivity of 3,668 S·cm−1. Thanks to the high adhesion of the elastic conductors, the resulted e-textiles could withstand repeated stretching, folding, and machine washing (20 times) without obvious performance decay, which reveals its potential application in consumable e-textiles.

Selective semihydrogenation of alkynes has been a long-term and significant target, yet it remains a great challenge. Herein, bimetallic nanoparticles in a metal–organic framework (MOF), i.e., CuPd...

Single-atom catalysts (SACs) have sparked broad interest recently while the low metal loading poses a big challenge for further applications. Herein, a dual protection strategy has been developed to give high-content SACs by nanocasting SiO2 into porphyrinic metal–organic frameworks (MOFs). The pyrolysis of SiO2@MOF composite affords single-atom Fe implanted N-doped porous carbon (FeSA–N–C) with high Fe loading (3.46 wt%). The spatial isolation of Fe atoms centered in porphyrin linkers of MOF sets the first protective barrier to inhibit the Fe agglomeration during pyrolysis. The SiO2 in MOF provides additional protection by creating thermally stable FeN4/SiO2 interfaces. Thanks to the high-density FeSA sites, FeSA–N–C demonstrates excellent oxygen reduction performance in both alkaline and acidic medias. Meanwhile, FeSA–N–C also exhibits encouraging performance in proton exchange membrane fuel cell, demonstrating great potential for practical application. More far-reaching, this work grants a general synthetic methodology toward high-content SACs (such as FeSA, CoSA, NiSA).

The high surface energy of nanomaterials endows them a metastable nature, which greatly limits their application. However, in some cases, the degradation process derived from the poor stability of nanomaterials offers an unconventional approach to design and obtain functional nanomaterials. Herein, based on the poor stability of ZnSe-[DETA]0.5 hybrid nanobelts, we developed a new strategy to chemically graphitize and functionalize graphene oxide (GO). When ZnSe[DETA]0.5 hybrid nanobelts encountered a strong acid, they were attacked by H+ cations and could release highly reactive Se2− anions into the reaction solution. Like other common reductants (such as N2H4·H2O), these Se2− anions exhibited an excellent ability to restore the structure of GO. The structural restoration of GO was greatly affected by the reaction time, the volume of HCl, and the mass ratio between GO and ZnSe[DETA]0.5 nanobelts. By carefully controlling the reaction process and the post-processing process, we finally obtained several Se-based reduced GO (RGO) nanocomposites (such as ZnSe/Se-RGO, ZnSe-RGO, and Se-RGO) and various selenide/metal-RGO nanocomposites (such as Ag2Se-RGO, Cu2Se-RGO, and Pt-RGO). Although the original structure and composition of ZnSe[DETA]0.5 nanobelts are destroyed, the procedure presents an unconventional way to chemically graphitize and functionalize GO and thus provides a new material synthesis platform for nanocomposites.

Photoelectrochemical (PEC) hydrogen production is of great interest as an ideal avenue towards clean and renewable energy. However, the instability and low energy conversion efficiency of photoanodes hinder their practical applications. Here we address these issues by introducing a hole extraction layer (HEL) which could rapidly transfer and consume photogenerated holes. The HEL is constructed by reduced graphene oxide (RGO) and other cocatalysts that enable rapid transfer and subsequent consumption of holes, respectively. Specifically, we showcase a high-stability photoanode composed of CdSeTe nanowires (CST NWs) and RGO/PdS nanoparticles (PdS NPs) based HEL. The photoanode achieves excellent photocorrosion resistance, which allows stable hydrogen evolution for > 2 h at 0.5 VRHE.

Three-dimensional (3D) graphene networks are performance boosters for functional nanostructures in energy-related fields. Although tremendous intriguing nanostructures-decorated 3D graphene network...

Owing to the stimulus-responsive and dynamic properties, magnetism-driven assembly of building blocks to form ordered structures is always a marvelous topic. While abundant magnetic assemblies have been developed in ideal physical and chemical conditions, it remains a challenge to realize magnetic assembly in complicated biological systems. Herein, we report a kind of biomacromolecule-modified magnetic nanosheets, which are mainly composed of superparamagnetic graphene oxide (γ-Fe2O3@GO), the tumor-targeting protein transferrin (TF), and the mitochondrion-targeting peptide (MitP). Such large-size nanosheets (0.5–1 μm), noted as L-Fe2O3@GO-MitP-TF, can successfully in situ assemble on the surface of tumor cells in a size-dependent and tumor cell-specific way, leading to severe inhibition of nutrient uptake for the tumor cells. More significantly, the nanostructures could efficiently confine the tumor cells, preventing both invasion and metastasis of tumor cells both in vitro and in vivo. Moreover, the 2D assemblies could remarkably disrupt the mitochondria and induce apoptosis, remarkably eradicating tumors under near-infrared (NIR) irradiation. This study sheds light on the development of new nano-systems for efficient cancer therapy and other biomedical applications.

Selective and efficient catalytic conversion of carbon dioxide (CO2) into value-added fuels and feedstocks provides an ideal avenue to high-density renewable energy storage. An impediment to enabling deep CO2 reduction to oxygenates and hydrocarbons (e.g., C2+ compounds) is the difficulty of coupling carbon-carbon bonds efficiently. Copper in the +1 oxidation state has been thought to be active for catalyzing C2+ formation, whereas it is prone to being reduced to Cu0 at cathodic potentials. Here we report that catalysts with nanocavities can confine carbon intermediates formed in situ, which in turn covers the local catalyst surface and thereby stabilizes Cu+ species. Experimental measurements on multihollow cuprous oxide catalyst exhibit a C2+ Faradaic efficiency of 75.2 ± 2.7% at a C2+ partial current density of 267 ± 13 mA cm-2 and a large C2+-to-C1 ratio of ∼7.2. Operando Raman spectra, in conjunction with X-ray absorption studies, confirm that Cu+ species in the as-designed catalyst are well retained during CO2 reduction, which leads to the marked C2+ selectivity at a large conversion rate.

The general synthesis and control of the coordination environment of single-atom catalysts (SACs) remains a great challenge. Herein, a general host-guest cooperative protection strategy has been developed to construct SACs by introducing polypyrrole (PPy) into a bimetallic metal-organic framework. As an example, the introduction of Mg2+ in MgNi-MOF-74 extends the distance between adjacent Ni atoms; the PPy guests serve as N source to stabilize the isolated Ni atoms during pyrolysis. As a result, a series of single-atom Ni catalysts (named NiSA -Nx -C) with different N coordination numbers have been fabricated by controlling the pyrolysis temperature. Significantly, the NiSA -N2 -C catalyst, with the lowest N coordination number, achieves high CO Faradaic efficiency (98 %) and turnover frequency (1622 h-1 ), far superior to those of NiSA -N3 -C and NiSA -N4 -C, in electrocatalytic CO2 reduction. Theoretical calculations reveal that the low N coordination number of single-atom Ni sites in NiSA -N2 -C is favorable to the formation of COOH* intermediate and thus accounts for its superior activity.

A considerable challenge in the conversion of carbon dioxide into useful fuels comes from the activation of CO2 to CO2 .- or other intermediates, which often requires precious-metal catalysts, high overpotentials, and/or electrolyte additives (e.g., ionic liquids). We report a microwave heating strategy for synthesizing a transition-metal chalcogenide nanostructure that efficiently catalyzes CO2 electroreduction to carbon monoxide (CO). We found that the cadmium sulfide (CdS) nanoneedle arrays exhibit an unprecedented current density of 212 mA cm-2 with 95.5±4.0 % CO Faraday efficiency at -1.2 V versus a reversible hydrogen electrode (RHE; without iR correction). Experimental and computational studies show that the high-curvature CdS nanostructured catalyst has a pronounced proximity effect which gives rise to large electric field enhancement, which can concentrate alkali-metal cations resulting in the enhanced CO2 electroreduction efficiency.

As a non-invasive therapeutic method without penetration-depth limitation, magnetic hyperthermia therapy (MHT) under alternating magnetic field (AMF) is a clinically promising thermal therapy. However, the poor heating conversion efficiency and lack of stimulus–response obstruct the clinical application of magnetofluid-mediated MHT. Here, we develop a ferrimagnetic polyethylene glycol-poly(2-hexoxy-2-oxo-1,3,2-dioxaphospholane) (mPEG-b-PHEP) copolymer micelle loaded with hydrophobic iron oxide nanocubes and emodin (denoted as EMM). Besides an enhanced magnetic resonance (MR) contrast ability (r2 = 271 mM−1 s−1) due to the high magnetization, the specific absorption rate (2518 W/g at 35 kA/m) and intrinsic loss power (6.5 nHm2/kg) of EMM are dozens of times higher than the clinically available iron oxide nanoagents (Feridex and Resovist), indicating the high heating conversion efficiency. Furthermore, this composite micelle with a flowable core exhibits a rapid response to magnetic hyperthermia, leading to an AMF-activated supersensitive drug release. With the high magnetic response, thermal sensitivity and magnetic targeting, this supersensitive ferrimagnetic nanocomposite realizes an above 70% tumor cell killing effect at an extremely low dosage (10 μg Fe/mL), and the tumors on mice are completely eliminated after the combined MHT–chemotherapy.

Electrochemical reduction of carbon dioxide (CO2) to value-added chemicals and fuels offers a potential platform to store renewable energy in chemical bonds and thus a route to carbon recycling. Due to its high efficiency and reasonable economic feasibility, the conversion of CO2 to carbon monoxide (CO) is considered as the most promising candidate reaction in the industrial market. Recently, the understanding of the basic mechanism of CO2 reduction to CO has become clearer, which has also motivated the design principles for better-performing catalysts including morphology, size, grain boundary, and surface engineering. Various catalysts (noble and non-noble metals, transition metal chalcogenides, carbon materials, and molecular catalysts) have been developed to efficiently catalyze the CO2-to-CO conversion. Here we survey recent key progress in CO2-to-CO conversion in the field of electrocatalytic CO2 reduction. We will highlight the principles of designing electrocatalysts for the selective formation of CO, the influence of electrolytes on the selectivity and conversion rate, and the emerging applications of electrolyzers for large-scale CO production. We finally provide an outlook on several development opportunities that could lead to new advancements in this promising research field.

Ubiquitous petrochemical-based plastics pose a potential threat to ecosystems. In response, bioderived and degradable polymeric materials are being developed, but their mechanical and thermal properties cannot compete with those of existing petrochemical-based plastics, especially those used as structural materials. Herein, we report a biodegradable plant cellulose nanofiber (CNF)-derived polymeric structural material with high-density reversible interaction networks between nanofibers, exhibiting mechanical and thermal properties better than those of existing petrochemical-based plastics. This all-green material has substantially improved flexural strength (∼300 MPa) and modulus (∼16 GPa) compared with those of existing petrochemical-based plastics. Its average thermal expansion coefficient is only 7 × 10-6 K-1, which is more than 10 times lower than those of petrochemical-based plastics, indicating its dimension is almost unchanged when heated, and thus, it has a thermal dimensional stability that is better than those of plastics. As a fully bioderived and degradable material, the all-green material offers a more sustainable high-performance alternative to petrochemical-based plastics.

Amorphous calcium carbonate (ACC) plays a key role as transient precursor in the early stages of biogenic calcium carbonate formation in nature. However, due to its instability in aqueous solution, there is still rare success to utilize ACC in biomedicine. Here, we report the mutual effect between paramagnetic gadolinium ions and ACC, resulting in ultrafine paramagnetic amorphous carbonate nanoclusters (ACNC) in the presence of both gadolinium occluded highly hydrated ACC-like environment and poly(acrylic acid). Gadolinium is confirmed to enhance the water content in ACC, and the high water content of ACNC (23 molecules H2O per 1 Gd) contributes to the much enhanced magnetic resonance imaging (MRI) contrast efficiency compared with commercially available gadolinium-based contrast agents. Furthermore, the enhanced T1 weighted MRI performance and biocompatibility of ACNC are further evaluated in various animals including rat, rabbit and beagle dog, in combination with promising safety in vivo. Overall, exceptionally facile mass-productive ACNC exhibits superb imaging performance and impressive stability, which provides a promising strategy to design MR contrast agents.

Dynamic soft materials are requisite components not only for the survival of organisms in complicated natural environments but also for the advancement and operation of smart devices. A recently published article ( Zhao et al. ) reports new tunable polymeric materials exhibiting excellent reversible properties when the network hydration state is varied.

Many platinum group metal-free inorganic catalysts have demonstrated high intrinsic activity for diverse important electrode reactions, but their practical use often suffers from undesirable structural degradation and hence poor stability, especially in acidic media. We report here an alkali-heating synthesis to achieve phase-mixed cobalt diselenide material with nearly homogeneous distribution of cubic and orthorhombic phases. Using water electroreduction as a model reaction, we observe that the phase-mixed cobalt diselenide reaches the current density of 10 milliamperes per square centimeter at overpotential of mere 124 millivolts in acidic electrolyte. The catalyst shows no sign of deactivation after more than 400 h of continuous operation and the polarization curve is well retained after 50,000 potential cycles. Experimental and computational investigations uncover a boosted covalency between Co and Se atoms resulting from the phase mixture, which substantially enhances the lattice robustness and thereby the material stability. The findings provide promising design strategy for long-lived catalysts in acid through crystal phase engineering., Noble-metal-free catalysts often show stability issues in acidic media due to structural degradation. Here authors show that phase-mixed engineering of cobalt diselenide electrocatalysts can enable greater covalency of Co-Se bonds and improve robustness for catalyzing hydrogen evolution in acid.

The upgrading of CO2/CO feedstocks to higher-value chemicals via energy-efficient electrochemical processes enables carbon utilization and renewable energy storage. Substantial progress has been made to improve performance at the cathodic side; whereas less progress has been made on improving anodic electro-oxidation reactions to generate value. Here we report the efficient electroproduction of value-added multi-carbon dimethyl carbonate (DMC) from CO and methanol via oxidative carbonylation. We find that, compared to pure palladium controls, boron-doped palladium (Pd-B) tunes the binding strength of intermediates along this reaction pathway and favors DMC formation. We implement this doping strategy and report the selective electrosynthesis of DMC experimentally. We achieve a DMC Faradaic efficiency of 83 ± 5%, fully a 3x increase in performance compared to the corresponding pure Pd electrocatalyst., The electro-oxidative synthesis of valued chemicals offers to enhance the overall efficiency and economic viability of renewable electrosynthesis systems. Here, the authors use dopant-tuned catalysts to promote the electrosynthesis of dimethyl carbonate from CO and methanol via oxidative carbonylation.

The anode oxygen evolution reaction (OER) is known to largely limit the efficiency of electrolyzers owing to its sluggish kinetics. While crystalline metal oxides are promising as OER catalysts, their amorphous phases also show high activities. Efforts to produce amorphous metal oxides have progressed slowly, and how an amorphous structure benefits the catalytic performances remains elusive. Now the first scalable synthesis of amorphous NiFeMo oxide (up to 515 g in one batch) is presented with homogeneous elemental distribution via a facile supersaturated co-precipitation method. In contrast to its crystalline counterpart, amorphous NiFeMo oxide undergoes a faster surface self-reconstruction process during OER, forming a metal oxy(hydroxide) active layer with rich oxygen vacancies, leading to superior OER activity (280 mV overpotential at 10 mA cm-2 in 0.1 m KOH). This opens up the potential of fast, facile, and scale-up production of amorphous metal oxides for high-performance OER catalysts.

Summary Biomimetic bulk structural materials have been paid increasing attention for their huge application prospects. Integrating close-to-ideal, ultrathin, and flexible nanostructured units into high-performance nacreous bulk nanocomposites is worth considering yet remains challenging due to the elusive micro- and nano-interface connections. Here, by introducing a multiscale soft-rigid polymer dual-network interfacial design strategy that enables us to appropriately reinforce the nanoscale building blocks or their bridging, we can construct a type of nacreous bulk nanocomposites with tunable mechanical properties in the mild, eco-friendly, and highly efficient bottom-up assembly process. The resultant nanocomposites can achieve continuously reinforced mechanical transformation without experiencing environmentally threatening interfacial manipulation processes. This interfacial design strategy, supported by sufficient experiments and simulations, endows the assembled nacreous nanocomposite with superior mechanical enhancement and improved stability under high humidity and temperature conditions. Combined with the scalable assembly technique, it will pave the way for the design of high-performance biomimetic bulk nanocomposites for structural applications.

Molybdenum disulfide (MoS2) has been intensively investigated for its high theoretical capacity as an advanced anode material for lithium storage. However, the low electronic conductivity and frail layered structure give rise to its poor cycling stability and low rate performance. Herein, by taking advantages of the porous structure and the high N content of metal-organic frameworks (MOFs) derivatives, a facile and scalable method combining electrospinning and following a hydrothermal process was developed to fabricate MoS2-based composite fibers, in which ultrathin MoS2 nanoplates were vertically assembled on the polyacrylonitrile-MOF-derived N-doped porous carbon nanofibers (PCNF). As expected, benefiting from the hierarchical structure of PCNF and the synergies between MoS2 and PCNF, the obtained PCNF@MoS2 exhibited high capacity and cycling performance in a lithium battery.

Designing high-efficiency catalyst is at the heart of a transition to future renewable energy systems. Great achievements have been made to optimize thermodynamics to reduce energetic barriers of the catalytic reactions. However, little attention has been paid to design catalysts to improve kinetics to enrich the local concentration of reactant molecules surrounding electrocatalysts. Here, we find that well-designed nanocatalysts with periodic structures can optimize kinetics to accelerate mass-transport from bulk electrolyte to the catalyst surface, leading to the enhanced catalytic performance. This achievement stems from regulation of the surface reactant flux due to the gradient of the microelectric field directing uniformly to the nearest catalyst on ordered pattern, so that all of the reactant molecules are utilized sufficiently for reactions, enabling the boost of the electrocatalytic performance. This novel concept is further confirmed in various catalytic systems and nanoassemblies, such as nanoparticles, nanorods, and nanoflakes.

The incorporation of defects, such as vacancies, into functional materials could substantially tailor their intrinsic properties. Progress in vacancy chemistry has enabled advances in many technological applications, but creating new type of vacancies in existing material system remains a big challenge. We show here that ionized nitrogen plasma can break bonds of iron-carbon-nitrogen-nickel units in nickel-iron Prussian blue analogues, forming unconventional carbon-nitrogen vacancies. We study oxygen evolution reaction on the carbon-nitrogen vacancy-mediated Prussian blue analogues, which exhibit a low overpotential of 283 millivolts at 10 milliamperes per square centimeter in alkali, far exceeding that of original Prussian blue analogues and previously reported oxygen evolution catalysts with vacancies. We ascribe this enhancement to the in-situ generated nickel-iron oxy(hydroxide) active layer during oxygen evolution reaction, where the Fe leaching was significantly suppressed by the unconventional carbon-nitrogen vacancies. This work opens up opportunities for producing vacancy defects in nanomaterials for broad applications., Defect-engineering offers a promising route to vary material properties and reactivities, although the achievable defect types are limited. Here, the authors introduced unusual CN-vacancies in Prussian blue analogue pre-catalysts that can limit Fe leaching and improve oxygen evolution performances.

Lithium metal based anode with hierarchical structure to enable high rate capability, volume change accommodation, and dendritic suppression is highly desirable for all-solid-state lithium metal battery. However, the fabrication of hierarchical lithium metal based anode is challenging due to the volatility of lithium. Here, we report that natural diatomite can act as an excellent template for constructing hierarchical silicon-lithium based hybrid anode for high performance all-solid-state lithium metal battery. This hybrid anode exhibits stable lithium stripping/plating performance over 1000 h with average overpotential lower than 100 mV without any short circuit. Moreover, all-solid-state full cell using this lithium metal composite anode to couple with lithium iron phosphate cathode shows excellent cycling stability (0.04% capacity decay rate for 500 cycles at 0.5C) and high rate capability (65 mAh g−1 at 5C). The present natural diatomite derived hybrid anode could further promote the fabrication of high performance all-solid-state lithium batteries from sustainable natural resources., Lithium metal is the anode of choice for the next-generation high energy density batteries. To address the key technological challenges, the authors report a hybrid Li anode design with hierarchical pores structure derived from natural diatomite and improved electrochemical performance in all-solid-state lithium batteries.

Bio-sourced nanocellulosic materials are promising candidates for spinning high-performance sustainable macrofibers for advanced applications. Various strategies have been pursued to gain nanocellulose-based macrofibers with improved strength. However, nearly all of them have been achieved at the expense of their elongation and toughness. Inspired by the widely existed hierarchical helical and nanocomposite structural features in biosynthesized fibers exhibiting exceptional combinations of strength and toughness, we report a design strategy to make nanocellulose-based macrofibers with similar characteristics. By combining a facile wet-spinning process with a subsequent multiple wet-twisting procedure, we successfully obtain biomimetic hierarchical helical nanocomposite macrofibers based on bacterial cellulose nanofibers, realizing impressive improvement in their tensile strength, elongation and toughness simultaneously. The achievement certifies the validity of the bioinspired hierarchical helical and nanocomposite structural design proposed here. This bioinspired design strategy provides a potential platform for further optimizing or creating many more strong and tough nanocomposite fiber materials for diverse applications.

Summary Identifying the optimal synthetic and structural parameters in preparing pyrolyzed metal/nitrogen/carbon (M/N/C) materials is crucial for developing effective catalysts for many important catalytic processes. Here we report a group of mesoporous Co/N/C catalysts ranging from polymerized cobalt porphyrin to Co/N-doped carbons, which are prepared by pyrolysis of cobalt porphyrin using silica nanoparticles as templates at different temperatures, for boosting both heterogeneous catalysis and electrocatalysis. It is revealed that the polymerized cobalt porphyrin prepared at low temperature (500°C) is a polymer-like network with exclusive single-atom Co-Nx sites, and that the high-temperature-pyrolysis (>600°C) produces an electrically conductive Co/N-doped carbon, accompanied by part degradation of Co-Nx centers. We identify that the polymerized cobalt porphyrin with undecomposed Co-Nx centers is optimal for heterogeneous catalytic oxidation of ethylbenzene, whereas the electrically conductive Co/N-doped carbon is ideal for eletrocatalytic oxygen reduction. Our results provide new insights for rationally optimizing M/N/C catalysts for different reactions., Graphical Abstract, Highlights • A group of mesoporous Co/N/C catalysts have been successfully prepared • HAADF-STEM and XAFS reveal structural and componential information of the catalysts • The difference in optimizing Co/N/C catalysts for different reactions is identified, Chemistry; Inorganic Chemistry; Catalysis

The design of highly efficient non-noble-metal electrocatalysts for large-scale hydrogen production remains an ongoing challenge. We report here a Ni2P nanoarray catalyst grown on a commercial Ni foam substrate, which demonstrates an outstanding electrocatalytic activity and stability in basic electrolyte. The high catalytic activity can be attributed to the favorable electron transfer, superior intrinsic activity, and the intimate connection between the nanoarrays and their substrate. Moreover, the unique "superaerophobic" surface feature of the Ni2P nanoarrays enables a remarkable capability to withstand internal and external forces and release the in situ generated H2 bubbles in a timely manner at large current densities (such as >1000 mA cm-2) where the hydrogen evolution becomes vigorous. Our results highlight that an aerophobic structure is essential to catalyze gas evolution for large-scale practical applications.

Cubic phase CsPbI3 quantum dots (α-CsPbI3 QDs) as a newly emerging type of semiconducting QDs hold tremendous promise for fundamental research and optoelectronic device applications. However, stable and sub-5 nm-sized α-CsPbI3 QDs have rarely been demonstrated so far due to their highly labile ionic structure and low phase stability. Here, we report a novel strontium-substitution along with iodide passivation strategy to stabilize the cubic phase of CsPbI3, achieving the facile synthesis of α-CsPbI3 QDs with a series of controllable sizes down to sub-5 nm. We demonstrate that the incorporation of strontium ions can significantly increase the formation energies of α-CsPbI3 QDs and hence reduce the structure distortion to stabilize the cubic phase at the few-nanometer size. The size ranging from 15 down to sub-5 nm of as-prepared stable α-CsPbI3 QDs allowed us to investigate their unique size-dependent optical properties. Strikingly, the few-nanometer-sized α-CsPbI3 QDs turned out to retain high photolumine...

The rational design of assembled metal-organic frameworks (MOFs) derived carbon materials with rapid mass transport properties and stable porous structure is highly desirable yet a great challenge to date. In this work, MOFs-derived Co/N-doped porous carbon fibers with high electrochemical performance can be prepared simply by carbonizing MOFs nanofibers, which were fabricated by the electrospinning-assisted assembly of bimetallic zeolitic imidazolate framework nanoparticles (BMZIFs) based on ZIF-8 and ZIF-67. The effects of assembly and Zn/Co ratios on the oxygen reduction reaction (ORR) performances of the electrospun fibers derivatives were systematically studied. As expected, compared to the non-electrospun samples, such doped porous carbon nanofibers exhibited excellent electrocatalytic performances without any etching or other activating processes, and the sample with the molar ratio of Zn: Co= 5:1 even showed comparable ORR performance with the commercial Pt/C catalyst under the same conditions. The high catalytic performances root in the dense assembly of MOFs within the electrospun fibers, which was beneficial to endow the derivatives with the high surface area as well as uniform N and Co doping. Besides, the one-dimensional porous structure significantly promoted the mass transfer and exposure of active sites.

Hydrogel materials have many excellent properties and a wide range of applications. Recently, a new type of hydrogel has emerged: cellulose nanofiber (CNF)-based hydrogels, which have three-dimensional nanofiber networks and unique physical properties. Because CNFs are abundant, renewable, and biodegradable, they are green and eco-friendly nanoscale building blocks. In addition, CNF-based hydrogel materials exhibit excellent mechanical properties and designable functions by different preparation methods and structure designs, demonstrating huge development potential. In this Perspective, we summarize the recent progress in the development of CNF-based hydrogels and introduce their applications in elastic hydrogels, ionic conduction, water purification, and biomedicine, highlighting future trends and opportunities for the further development of CNF-based hydrogels as emerging materials systems.