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The development of redox-targeting co-catalysts is one of the important tasks in realizing hybrid photocatalytic systems for CO2 reduction reaction (CO2 RR), which has been sought after as a promis...

Li-polysulfide batteries (LPSBs) involving dissolved polysulfides as the catholyte have been sought as an alternative solution for addressing the problem of inefficient sulfur utilization with conventional lithium-sulfur batteries, but imposes even more stringent requirements on polysulfide immobilization. In this study, a hybrid rGO/CNTs aerogel embedding FeP nanocubes is fabricated by instantly freezing and phosphorizing metal organic frameworks (MOF)-containing precursors, and used as the LPSB cathodes for hosting polysulfides with high affinity. A high specific capacity of 1312.3 mA h g−1 at 0.2 C and prolonged cycling with only 0.037% decay per cycle at 1 C were achieved for over 500 cycles, together with an exceptional high areal capacity up to 8.5 mA h cm−2 at the sulfur loading of 9.6 mg cm−2. This remarkable LPSB performance is ascribed to the strong immobilization of polysulfides by the FeP anchoring material, the conductive and microporous carbon scaffolds in providing adequate interfaces for charge transfer, the homogeneous catholyte distribution for promoting sulfur utilization, as well as a possible catalytic effect of FeP on expediting the redox conversion of polysulfides.

Efficient water electrolysis for hydrogen production constitutes a key segment for the upcoming hydrogen economy, but has been impeded by the lack of high-performance and low-cost electrocatalysts ...

The urgent demand on high performance energy storage devices makes lithium sulfur batteries with a high energy density up to 2600 Wh kg−1 extremely attractive. However, the low capacity reversibility and poor rate capability still pose a significant hurdle on their real-world applications. Here, a freestanding thin-film composite containing sulfurized polyacrylonitrile with conductive backbone of carbon nanotubes has been fabricated by an electrospinning method followed by vulcanization, and employed as the binder-free cathode for lithium sulfur batteries without any aid of current collectors. A synergic effect from sulfur and carbon nanotubes, when co-spun together, has been discovered on promoting the electrochemical performance of the cathodes by simultaneously creating material porosity and conductive pathway. The optimized composite fibers made from a ternary precursor solution containing 20% carbon nanotubes present the best performance, delivering a high initial discharge capacity of 1610 mAh g−1 at 0.2C and outstanding cycle stability of 1106 mAh g−1 at 1C over 500 cycles. It is anticipated that the porous composite nanofibers and the multi-variant fabrication methodology reported here can be extended to more energy storage applications, particularly for flexible lithium sulfur batteries.

A facile and general strategy is presented to create well-defined heterojunctions with ultra-small multimetallic sulfide nanoparticles (MMSNPs) uniformly coated on sliver nanowires. A unique aspect of this method is the atomic-level pre-integration of multimetallic components by exploiting recently developed supertetrahedral metal sulfide nanoclusters. The use of such nanoclusters also enables the convenient formation of the ultrathin interfacial Ag2 S layer via etching. The heterojunctions (denoted as MMSNPs/Ag2 S/Ag-NWs) benefit from adjustable multimetallic components and display tunable visible-light-driven photocatalytic performance owing to the synergistic effect of multimetallic components from MMSNPs and the high carrier mobility of Ag-NWs. The synthetic strategy opens new routes to designing and fabricating various heterojunctions with multimetallic components, which could further expand their applications in catalysis, electronics, and photonics.

A special Cu(NO3)2 thin solution layer was built on highly hydrophilic mica surfaces and subjected to rapid evaporation. Controlling the evaporation time can intentionally manipulate the supersaturation. Morphology-selective synthesis of nanoplate- or microsphere-like Cu(NO3)2·2.5H2O micro/nanostructures has been succeeded by alternatively boosting either the heterogeneous nucleation at the substrate–solution interface at a low supersaturation level or the homogeneous nucleation in the bulk solution phase at a high supersaturation level. Our study presents a new method for morphology-selective synthesis of micro/nanostructures, which should also be applicable to materials other than Cu(NO3)2·2.5H2O and shall actually promote their applications. As a demonstration, Cu(NO3)2·2.5H2O micro/nanostructures were converted into porous CuO with well-preserved starting morphologies. The hierarchical porous CuO micro/nanostructures exhibited easily recyclable high photocatalytic activity towards visible-light degradation of methylene blue (MB).

Microfibrillar biochars of chitin (CTF), chitosan (CSF), and cellulose (CLF) were fabricated via green homogenization and a pyrolysis process, and were subsequently explored as adsorbents for removing over-released sodium benzoate (SB) in aqueous systems. The structure, composition, morphology, and adsorption behavior of the as-fabricated biochars were characterized. Results suggest that all biochars, with a microscaled fibrillar structure and foam-like network morphology, underwent severe chemical transition during the pyrolysis process, thereby causing an enhancement of the Brunauer–Emmett–Teller surface area, pore volume, and aromatic and carbonaceous composition. Consequently, N-doped porous CTF/CSF microfibrillar biochars displayed a distinguished capture capacity toward SB compared to that of their fibrillar precursors. Tailoring the chemical composition, porous structure, and sorption mechanism constitutes a possible strategy to achieve adequate structural effects of polysaccharide microfibrillar chars for potential application in environmental treatment or bioenergy.

Biomimetic channels based on carbon nanotubes (CNTs) with fast and selective transport have attractive applications in many fields. In this work, a remarkable and modulated enhancement in the ion transport rate through CNTs is facilitated by means of lipid decoration, by a factor of up to 20 times. A type of CNT membrane is firstly prepared, composed of well aligned multi-wall carbon nanotubes with an inner size of ∼10 nm. An inter-diffusion method is used to efficiently incorporate lipids within the CNTs. It is found that the lipid phase state as well as the surface property of the tubes' inner walls corporately determine the assembly behavior, such as location and stability of lipids, which further influence the ion transport rate through the tubes. For example, the incorporation and self-assembly of liquid-phase DOPC and polymerized Diyne-PC within the tubes induces an enhancement in steady ion transport rate through CNTs by a factor of 5 and 20 times, respectively. In contrast, the gel-phase DPPC prefers to stay at tube tips, which increases the ion transport rate during the initial stage only. This work provides a practical guide to regulate the ion transport behaviors through CNTs for versatile applications.

Two types of out-of-substrate Ag–Ag2O nanoplates were grown on a ZnO substrate through a surfactantless photochemical method. First, the in situ photochemically synthesized Ag–Ag2O nanoparticles further crystallized into nanoplate-like superstructures with rough surfaces and ragged edges. The nanoparticle-mediated crystallization process was governed by a layer-by-layer crystallization mechanism. Our study should help fundamentally understand the formation mechanism of hierarchical nanoparticle superstructures. Under continuous UV illumination, the hundreds of nanometer-sized rough nanoplates (i.e., the nanoplate-like superstructures of nanoparticles) can be transformed into large smooth nanoplates with sizes of up to several micrometers. The out-of-substrate Ag–Ag2O nanoplates/ZnO heterostructures are potentially promising for photocatalytic applications.

Utilization of microbes as the carbon source and structural template to fabricate porous carbon has incentivized great interests owing to their diverse micromorphology and intricate intracellular structure, apart from the obvious benefit of "turning waste into wealth." Challenges remain to preserve the biological structure through the harsh and laborious post-synthetic treatments, and tailor the functionality as desired. Herein, Escherichia coli is directly coated with metal-organic frameworks (MOFs) through in situ assembly to fabricate N, P co-doped porous carbon capsules expressing self-phosphorized metal phosphides. While the MOF coating serves as an armoring layer for facilitating the morphology inheritance from the bio-templates and provides metal sources for generating extra porosity and electrochemically active sites, the P-rich phospholipids and N-rich proteins from the plasma membrane enable carbon matrix doping and further yield metal phosphides. These unique structural and compositional features endow the carbon capsules with great capabilities in suppressing polysulfide shuttling and catalyzing reversible oxygen conversion, ultimately leading to the superb performance of lithium-sulfur batteries and zinc-air batteries. Combining the bio-templating strategy with hierarchical MOF assembly, this work opens a new avenue for the fabrication of highly porous and functional carbon for advanced energy applications.

Multifunctional electrocatalysts based on earth-abundant elements are key for the development of Integrated Energy Systems (IES) such as electrolytic water splitting powered by metal-air batteries. Herein, hierarchical CuCoNC nanowire arrays are constructed on copper foam, enriching multiple active species on the catalytic scaffolds that lead to remarkable trifunctional activities of OER with η10 = 245 mV, HER with η10 = 59 mV and ORR comparable to Pt/C. While for overall water splitting a cell voltage of only 1.78 V is required to achieve a high current density of 500 mA cm−2, for Zn-air batteries (ZABs) a highly stabilized round-trip efficiency of >58% is achieved for over 360 h under 10 mA cm−2. Ultimately, a highly efficient IES of ZAB-powered water splitting employing a single catalyst is demonstrated with a hydrogen evolution rate of 69 μL s−1, showcasing a smart material design in simultaneously achieving multi-functionality and maximizing the energy efficiency.

Lithium titanium oxyphosphate LiTiOPO 4 is synthesized by a solution route and modified with a carbon layer using polyvinylidene difluoride as carbon source. It is demonstrated that the performance of LiTiOPO 4 strongly depends on cycling potential range. In the potential range from 0.5 to 3.0 V, limited capacity (less than 161 mA h g −1 ) is obtained, which is ascribed to a mechanism involving the insertion of lithium ions into vacant sites of crystalline structure. As the cut-off potential is set down to 0.1 V, a conversion of LiTiOPO 4 occurs in the initial cycle, as a result, a relative high and reversible capacity of 285 mA h g −1 at the current rate of 0.1 C can be achieved during the subsequent cycles. However, resembling that of transition metal oxides, possible charging/discharging mechanism, in this case, may involve the formation and decomposition of Li 2 O formed in the conversion of LiTiOPO 4 . The new strategy also enables LiTiOPO 4 as the electrode material with superior cycleability and rate capability of 195 mA h g −1 at the current rate of 2.0 C. The results indicate that carbon-coated LiTiOPO 4 could be a promising anode material with relative high capacity and good rate capability for lithium ion batteries.

A series of fulleropyrrolidine derivatives (FPx, x = 1–8) with alternating N-phenyl or N-methyl group were prepared as acceptors for polymer solar cells (PSCs) with the purpose of investigating the effect of N-substitutions on the photovoltaic properties of fullerene materials. More importantly, the morphology studies by means of atomic force microscopy (AFM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and space charge limited current (SCLC) measurements revealed that FP1 with N-phenyl group possessed not only appropriate miscibility with P3HT but also high electron mobility, which may account for its optimal photovoltaic properties.

A new approach using polypyrrole as the nitrogen source has been demonstrated for the fabrication of nitrogen-doped graphene, which subsequently served as nucleation centers for the growth of metal oxides. The thin layers of the nitrogen-doped graphene are not only used as conductive pathways accelerating the electrical conductivity of metal oxides but also serve as buffer layers to improve the electrical contact with metal oxide nanostructures during the delithiation/lithiation of lithium ions. As anodes for lithium ion batteries, the nitrogen-doped graphene and their hybrids with MnO2 nanorods exhibit exceptionally excellent capacity retention for 3000 cycles at 2500 mA g−1, and ultrafast rate capability, which pave the way for developing electrode materials for long cycle-life energy storage devices.

In this paper we demonstrate a novel complex array structure comprising well-aligned Au nanorods (10 nm in diameter) encapsulated inside 15 nm radius multiwalled carbon nanotubes (MWCNTs). A pre-aligned and open-ended nanoporous MWCNT membrane is used as the starting material. Au nanorods are precisely deposited and aligned inside the hollow channels of CNTs by inter-diffusing the HAuCl4 precursor and the reductant solution. Ultra-long Au nanowires and spherical Au nanoparticles are also observed in the CNT cavity with the same diameter in special cases. Using high-resolution TEM (HRTEM), scanning transmission electron microscopy (STEM), 3-dimensional TEM (3D-TEM) and energy dispersive X-ray spectroscopy (EDX), the precise location and composition of the encapsulated Au components with various structures are confirmed. This aligned Au@CNT endohedral material has important potential applications in nanocatalysis, waveguides, as well as in novel plasmonic devices.

In this paper crystalline noble metallic nanorods including Au and Ag with sub-10 nm diameter, are encapsulated within prealigned and open-ended multiwall carbon nanotubes (MWCNTs) through an electrodeposition method. As the external surface of CNTs has been insulated by the epoxy the CNT channel becomes the only path for the mass transport as well as the nanoreactor for the metal deposition. Highly crystallized Au and Ag2O nanorods parallel to the radial direction of CNTs are confirmed by high-resolution transmission electron microscopy, energy dispersive x-ray spectroscopy and x-ray powder diffraction spectroscopy. The Ag2O nanorods are formed by air oxidation on the Ag metals and show a single crystalline structure with (111) planes. The Au nanorods exhibit a complex crystalline structure including twin-crystal and lattice dislocation with (111) and (200) planes. These crystalline noble metallic nanostructures may have important applications for nanocatalysts for fuel cells as well as nanoelectronic and nanophotonic devices. This method is deemed to benefit the precise deposition of other crystalline nanostructures inside CNTs with a small diameter.