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Bismuth vanadate (BiVO 4 ) has been widely investigated as a photocatalyst or photoanode for solar water splitting, but its activity is hindered by inefficient cocatalysts and limited understanding of the underlying mechanism. Here we demonstrate significantly enhanced water oxidation on the particulate BiVO 4 photocatalyst via in situ facet-selective photodeposition of dual-cocatalysts that exist separately as metallic Ir nanoparticles and nanocomposite of FeOOH and CoOOH (denoted as FeCoO x ), as revealed by advanced techniques. The mechanism of water oxidation promoted by the dual-cocatalysts is experimentally and theoretically unraveled, and mainly ascribed to the synergistic effect of the spatially separated dual-cocatalysts (Ir, FeCoO x ) on both interface charge separation and surface catalysis. Combined with the H 2 -evolving photocatalysts, we finally construct a Z-scheme overall water splitting system using [Fe(CN) 6 ] 3−/4− as the redox mediator, whose apparent quantum efficiency at 420 nm and solar-to-hydrogen conversion efficiency are optimized to be 12.3% and 0.6%, respectively. Artificial photosynthesis offers an integrated means to convert light to fuel, but efficiencies are often low. Here, authors report a Z-scheme system utilizing Ir and FeCoO x co-catalysts to enhance charge separation on BiVO 4 facets that achieves high quantum efficiencies for overall water splitting.

Thermal-stimuli responsive nanomaterials hold great promise in designing multifunctional intelligent devices for a wide range of applications. In this work, a reversible isomeric transformation in an atomically precise nanocluster is reported. We show that biicosahedral [Au 13 Ag 12 (PPh 3 ) 10 Cl 8 ]SbF 6 nanoclusters composed of two icosahedral Au 7 Ag 6 units by sharing one common Au vertex can produce two temperature-responsive conformational isomers with complete reversibility, which forms the basis of a rotary nanomotor driven by temperature. Differential scanning calorimetry analysis on the reversible isomeric transformation demonstrates that the Gibbs free energy is the driving force for the transformation. This work offers a strategy for rational design and development of atomically precise nanomaterials via ligand tailoring and alloy engineering for a reversible stimuli-response behavior required for intelligent devices. The two temperature-driven, mutually convertible isomers of the nanoclusters open up an avenue to employ ultra-small nanoclusters (1 nm) for the design of thermal sensors and intelligent catalysts. Atomically precise metal nanoclusters are an emerging class of precision nanomaterials and hold potential in many applications. Here, the authors devise a [Au 13 Ag 12 (PPh 3 ) 10 Cl 8 ] + nanocluster with two conformational isomers that can reversibly convert in response to temperature, and hence acts as a rotary nanomotor.

Although much effort has been devoted to improving photoelectrochemical water splitting of hematite (α-Fe 2 O 3 ) due to its high theoretical solar-to-hydrogen conversion efficiency of 15.5%, the low applied bias photon-to-current efficiency remains a huge challenge for practical applications. Herein, we introduce single platinum atom sites coordination with oxygen atom (Pt-O/Pt-O-Fe) sites into single crystalline α-Fe 2 O 3 nanoflakes photoanodes (SAs Pt:Fe 2 O 3 -Ov). The single-atom Pt doping of α-Fe 2 O 3 can induce few electron trapping sites, enhance carrier separation capability, and boost charge transfer lifetime in the bulk structure as well as improve charge carrier injection efficiency at the semiconductor/electrolyte interface. Further introduction of surface oxygen vacancies can suppress charge carrier recombination and promote surface reaction kinetics, especially at low potential. Accordingly, the optimum SAs Pt:Fe 2 O 3 -Ov photoanode exhibits the photoelectrochemical performance of 3.65 and 5.30 mA cm −2 at 1.23 and 1.5 V RHE , respectively, with an applied bias photon-to-current efficiency of 0.68% for the hematite-based photoanodes. This study opens an avenue for designing highly efficient atomic-level engineering on single crystalline semiconductors for feasible photoelectrochemical applications. The achievable photocurrent of hematite, α-Fe 2 O 3 , is typically limited far below its theoretical limit. Here, the authors engineer single Pt atomic sites with surface oxygen vacancies into hematite photoanodes, which leads to enhanced photoelectrochemical water splitting.

Electrochemical conversion of nitrate to ammonia offers an efficient approach to reducing nitrate pollutants and a potential technology for low-temperature and low-pressure ammonia synthesis. However, the process is limited by multiple competing reactions and NO 3 − adsorption on cathode surfaces. Here, we report a Fe/Cu diatomic catalyst on holey nitrogen-doped graphene which exhibits high catalytic activities and selectivity for ammonia production. The catalyst enables a maximum ammonia Faradaic efficiency of 92.51% (−0.3 V(RHE)) and a high NH 3 yield rate of 1.08 mmol h −1 mg −1 (at − 0.5 V(RHE)). Computational and theoretical analysis reveals that a relatively strong interaction between NO 3 − and Fe/Cu promotes the adsorption and discharge of NO 3 − anions. Nitrogen-oxygen bonds are also shown to be weakened due to the existence of hetero-atomic dual sites which lowers the overall reaction barriers. The dual-site and hetero-atom strategy in this work provides a flexible design for further catalyst development and expands the electrocatalytic techniques for nitrate reduction and ammonia synthesis. Nitrate electroreduction to ammonia can decrease pollutants and produce high-value ammonia. Here, the authors design a Fe/Cu diatomic catalyst on nitrogen-doped graphene, which exhibits high catalytic activities of and selectivity for ammonia.

The restriction of structural vibration has assumed great importance in attaining bright emission of luminescent metal nanoclusters (NCs), where tremendous efforts are devoted to manipulating the surface landscape yet remain challenges for modulation of the structural vibration of the metal kernel. Here, we report efficient suppression of kernel vibration achieving enhancement in emission intensity, by rigidifying the surface of metal NCs and propagating as-developed strains into the metal core. Specifically, a layer-by-layer triple-ligands surface engineering is deployed to allow the solution-phase Au NCs with strong metal core-dictated fluorescence, up to the high absolute quantum yields of 90.3 ± 3.5%. The as-rigidified surface imposed by synergistic supramolecular interactions greatly influences the low-frequency acoustic vibration of the metal kernel, resulting in a subtle change in vibration frequency but a reduction in amplitude of oscillation. This scenario therewith impedes the non-radiative relaxation of electron dynamics, rendering the Au NCs with strong emission. The presented study exemplifies the linkage between surface chemistry and core-state emission of metal NCs, and proposes a strategy for brighter emitting metal NCs by regulating their interior metal core-involved motion. The photoluminescence of gold nanoclusters is affected by low-frequency acoustic vibrations. Here, the authors demonstrate that layer-by-layer ligand engineering can suppress such structural vibrations to achieve brighter emissions.

The electrocatalytic reduction of CO 2 to HCOOH (ERC-HCOOH) is one of the most feasible ways to alleviate energy crisis and solve environmental problems. Nevertheless, it remains a challenge for ERC-HCOOH to maintain excellent activity and selectivity in a wide potential window. Herein, ultra-thin flower-like Bi 2 O 2 CO 3 nanosheets (NSs) with abundant Bi-O structures were in situ synthesized on carbon paper via topological transformation and post-processing. Faraday efficiency of HCOOH (FE HCOOH ) reached 90% in a wide potential window (−1.5 to −1.8 V vs. Ag/AgCl). Significantly, excellent FE HCOOH (90%) and current density (47 mA·cm −2 ) were achieved at −1.8 V vs. Ag/AgCl. The X-ray absorption fine structure (XAFS) combined with density functional theory (DFT) calculation demonstrated that the excellent performance of Bi 2 O 2 CO 3 NS was attributed to the abundant Bi-O structures, which was conducive to enhancing the adsorption of CO 2 * and OCHO* intermediates and can effectively inhibit hydrogen evolution. The excellent performance of Bi 2 O 2 CO 3 NS over a wide potential window could provide new insights for the efficient electrocatalytic conversion of CO 2 .

Elucidating the synergistic catalytic mechanism between multiple active centers is of great significance for heterogeneous catalysis; however, finding the corresponding experimental evidence remains challenging owing to the complexity of catalyst structures and interface environment. Here we construct an asymmetric TeN 2 –CuN 3 double-atomic site catalyst, which is analyzed via full-range synchrotron pair distribution function. In electrochemical CO 2 reduction, the catalyst features a synergistic mechanism with the double-atomic site activating two key molecules: operando spectroscopy confirms that the Te center activates CO 2 , and the Cu center helps to dissociate H 2 O. The experimental and theoretical results reveal that the TeN 2 –CuN 3 could cooperatively lower the energy barriers for the rate-determining step, promoting proton transfer kinetics. Therefore, the TeN 2 –CuN 3 displays a broad potential range with high CO selectivity, improved kinetics and good stability. This work presents synthesis and characterization strategies for double-atomic site catalysts, and experimentally unveils the underpinning mechanism of synergistic catalysis. Elucidating the synergistic catalytic mechanism involving multiple active centers is of great significance for heterogeneous catalysis. Here the authors construct an asymmetric TeN 2 –CuN 3 double atomic site catalyst featuring synergistic CO 2 activation and H 2 O dissociation for CO 2 electroreduction.

Synthetic high-performance fibers present excellent mechanical properties and promising applications in the impact protection field. However, fabricating fibers with high strength and high toughness is challenging due to their intrinsic conflicts. Herein, we report a simultaneous improvement in strength, toughness, and modulus of heterocyclic aramid fibers by 26%, 66%, and 13%, respectively, via polymerizing a small amount (0.05 wt%) of short aminated single-walled carbon nanotubes (SWNTs), achieving a tensile strength of 6.44 ± 0.11 GPa, a toughness of 184.0 ± 11.4 MJ m −3 , and a Young’s modulus of 141.7 ± 4.0 GPa. Mechanism analyses reveal that short aminated SWNTs improve the crystallinity and orientation degree by affecting the structures of heterocyclic aramid chains around SWNTs, and in situ polymerization increases the interfacial interaction therein to promote stress transfer and suppress strain localization. These two effects account for the simultaneous improvement in strength and toughness. High-performance fibers are promising materials in the impact protection field but fabricating fibers with high strength and high toughness is challenging. Here, the authors polymerize carbon nanotubes into aramid fibers to simultaneously improve strength and toughness.

Complex metal nanoparticles distributed uniformly on supports demonstrate distinctive physicochemical properties and thus attract a wide attention for applications. The commonly used wet chemistry methods display limitations to achieve the nanoparticle structure design and uniform dispersion simultaneously. Solid-phase synthesis serves as an interesting strategy which can achieve the fabrication of complex metal nanoparticles on supports. Herein, the solid-phase synthesis strategy is developed to precisely synthesize uniformly distributed CoFe@FeO x core@shell nanoparticles. Fe atoms are preferentially exsolved from CoFe alloy bulk to the surface and then be carburized into a Fe x C shell under thermal syngas atmosphere, subsequently the formed Fe x C shell is passivated by air, obtaining CoFe@FeO x with a CoFe alloy core and a FeO x shell. This strategy is universal for the synthesis of MFe@FeO x (M = Co, Ni, Mn). The CoFe@FeO x exhibits bifunctional effect on regulating polysulfides as the separator coating layer for Li-S and Na-S batteries. This method could be developed into solid-phase synthetic systems to construct well distributed complex metal nanoparticles. Solid-phase synthesis strategy is promising for fabricating desired complex metal nanoparticles on supports. Here, the authors synthesize CoFe@FeOx core-shell nanoparticles as the separator coatings via precise solid-phase method which effectively regulates polysulfides for lithium/ sodium-sulfur batteries.

Carbon-based perovskite solar cells (C-PSCs) are widely accepted as stable, cost-effective photovoltaics. However, C-PSCs have been suffering from relatively low power conversion efficiencies (PCEs) due to severe electrode-related energy loss. Herein, we report the application of a single-atom material (SAM) as the back electrode in C-PSCs. Our Ti 1 –rGO consists of single titanium (Ti) adatoms anchored on reduced graphene oxide (rGO) in a well-defined Ti 1 O 4 -OH configuration capable of tuning the electronic properties of rGO. The downshift of the Fermi level notably minimizes the series resistance of the carbon-based electrode. By combining with an advanced modular cell architecture, a steady-state PCE of up to 20.6% for C-PSCs is finally achieved. Furthermore, the devices without encapsulation retain 98% and 95% of their initial values for 1,300 h under 1 sun of illumination at 25°C and 60 °C, respectively. Carbon materials are promising for perovskite solar cells but suffer from poor interfacial energy level alignment. Now, Zhang et al. show that Ti atomically dispersed in reduced graphene reduces energy losses improving device performance.