Multicomponent Ru-Based Alloys with a Face-Centered Cubic Structure Achieve High Activity and CO Tolerance for Hydrogen Oxidation Electrocatalysis.

The face-centered cubic (fcc) Ru exhibits great potential for the alkaline hydrogen oxidation reaction (HOR), while achieving high HOR activity and CO tolerance poses a formidable challenge for Ru catalysts in practical fuel cells, particularly when using CO-contaminated H, such as gray and blue hydrogen. Here, we propose a compositional diversification strategy to create 14 types of fcc Ru-based alloys, in which adjustable compositions can tune the nanostructure while offsetting the limitations of single Ru. Among them, quinary RuInPtNiCu nanocrystals (NCs) exhibit an outstanding HOR activity of 5.

Unveiling the Gold Facet Effect in Selective Oxidation of 5-Hydroxymethylfurfural and Hydrogen Production.

Direct oxidation of 5-hydroxymethylfurfural (HMF) to 5-hydroxymethyl-2-furancarboxylic acid (HMFCA), crucial for medical supply production, is hindered by overoxidation. We synthesized gold nanomaterials with distinct single-crystal facets, {111} in octahedra (OC), {100} in nanocubes (NCs), and {110} in rhombic dodecahedra (RD), to investigate the facet-dependent HMF oxidation. The Au RD achieved the spontaneous oxidation of HMF to HMFCA with stoichiometric hydrogen production, maintaining 95% carbon balance, 91% yield, and 98% selectivity.

Hollow Pt-Encrusted RuCu Nanocages Optimizing OH Adsorption for Efficient Hydrogen Oxidation Electrocatalysis.

As one of the best candidates for hydrogen oxidation reaction (HOR), ruthenium (Ru) has attracted significant attention for anion exchange membrane fuel cells (AEMFCs), although it suffers from sluggish kinetics under alkaline conditions due to its strong hydroxide affinity. In this work, we develop ternary hollow nanocages with Pt epitaxy on RuCu (Pt-RuCu NCs) as efficient HOR catalysts for application in AEMFCs. Experimental characterizations and theoretical calculations confirm that the synergy in optimized Pt-RuCu NCs significantly modifies the electronic structure and coordination environment of Ru, thereby balancing the binding strengths of H* and OH* species, which leads to a markedly enhanced HOR performance.

Water-Driven Stacking Structure Transformation of Ultrathin Ru Nanosheets for Efficient Hydrogen Evolution Reaction.

Ultrathin crystalline materials are a class of popular materials that can potentially exhibit fascinating physical and chemical properties dictated by their unique stacking freedom. However, it is challenging to achieve the controllable synthesis over their stacking structure for ultrathin crystalline materials. Herein, water is employed as a key regulatory factor to realize phase engineering in ultrathin nanosheets (NSs), thereby altering stacking faults to achieve distinct stacking arrangements.

Implementation of Digital Computing by Colloidal Crystal Engineering with DNA.

Toehold-mediated strand displacement (TMSD) provides a versatile toolbox for developing DNA digital computing systems. Although different logic circuits with diverse functions have achieved good performance in terms of complexity and scalability, most previous DNA logic circuits perform information processing only at the molecular level, and nonspecific signal leakages are often difficult to avoid. Here, we demonstrate the feasibility of constructing leakless digital computing systems in three-dimensionally ordered colloidal supercrystals.

A Biphasic Strategy to Synergistically Accelerate Activation and CO Spillover in Formic Acid Oxidation Catalysis.

Developing highly efficient and carbon monoxide (CO)-tolerant platinum (Pt) catalysts for the formic acid oxidation reaction (FAOR) is vital for direct formic acid fuel cells (DFAFCs), yet it is challenging due to the high energy barrier of direct intermediates (HCOO* and COOH*) as well as the CO poisoning issues associated with Pt alloy catalysts. Here we present a versatile biphasic strategy by creating a hexagonal/cubic crystalline-phase-synergistic PtPb/C (/-PtPb/C) catalyst to tackle the aforementioned issues. Detailed investigations reveal that /-PtPb/C can simultaneously facilitate the adsorption of direct intermediates while inhibiting CO adsorption, thereby significantly improving the activation and CO spillover.

Tuning Crystal Phase of Palladium-Selenium Nanowires for Enhanced Ethylene Glycol Electrocatalytic Oxidation.

Alcohol electrooxidation is pivotal for a sustainable energy economy. However, designing efficient electrocatalysts for this process is still a formidable challenge. Herein, palladium-selenium nanowires featuring distinct crystal phases: monoclinic PdSe and tetragonal PdSe for ethylene glycol electrooxidation reaction (EGOR) are synthesized.

What Elements Really Intercalate into Pd Lattice When Heated in Dimethylformamide?

Palladium hydrides (PdH) are pivotal in both fundamental research and practical applications across a wide spectrum. PdH nanocrystals, synthesized by heating in dimethylformamide (DMF), exhibit remarkable stability, granting them widespread applications in the field of electrocatalysis. However, this stability appears inconsistent with their metastable nature.

Space-tiled colloidal crystals from DNA-forced shape-complementary polyhedra pairing.

Generating space-filling arrangements of most discrete polyhedra nanostructures of the same shape is not possible. However, if the appropriate individual building blocks are selected (e.g.

Colloidal quasicrystals engineered with DNA.

In principle, designing and synthesizing almost any class of colloidal crystal is possible. Nonetheless, the deliberate and rational formation of colloidal quasicrystals has been difficult to achieve. Here we describe the assembly of colloidal quasicrystals by exploiting the geometry of nanoscale decahedra and the programmable bonding characteristics of DNA immobilized on their facets.

Ga-Modification Near-Surface Composition of Pt-Ga/C Catalyst Facilitates High-Efficiency Electrochemical Ethanol Oxidation through a C2 Intermediate.

In electrochemical ethanol oxidation reactions (EOR) catalyzed by Pt metal nanoparticles through a C2 route, the dissociation of the C-C bond in the ethanol molecule can be a limiting factor. Complete EOR processes producing CO were always exemplified by the oxidative dehydrogenation of C1 intermediates, a reaction route with less energy utilization efficiency. Here, we report a PtGa/C electrocatalyst with a uniform distribution of Ga over the nanoparticle surface for EOR that produces CO at medium potentials (>0.

High Chemical Potential Driven Amorphization of Pd-based Nanoalloys.

Amorphous metals and alloys are promising candidates for superior catalysts in many catalytic and electrocatalytic reactions. It is of great urgency to develop a general method to construct amorphous alloys and further clarify the growth mechanism in a wet-chemical system. Herein, inspired by the conservation of energy during the crystallization process, amorphous PdCu nanoalloys have been successfully synthesized by promoting the chemical potential of the building blocks in solution.

Open-channel metal particle superlattices.

Although tremendous advances have been made in preparing porous crystals from molecular precursors, there are no general ways of designing and making topologically diversified porous colloidal crystals over the 10-1,000 nm length scale. Control over porosity in this size range would enable the tailoring of molecular absorption and storage, separation, chemical sensing, catalytic and optical properties of such materials. Here, a universal approach for synthesizing metallic open-channel superlattices with pores of 10 to 1,000 nm from DNA-modified hollow colloidal nanoparticles (NPs) is reported.

Regioselective Deposition of Metals on Seeds within a Polymer Matrix.

We use scanning probe block copolymer lithography in a two-step sequential manner to explore the deposition of secondary metals on nanoparticle seeds. When single element nanoparticles (Au, Ag, Cu, Co, or Ni) were used as seeds, both heterogeneous and homogeneous growth occurred, as rationalized using the thermodynamic concepts of bond strength and lattice mismatch. Specifically, heterogeneous growth occurs when the heterobond strength between the seed and growth atoms is stronger than the homobond strength between the growth atoms.

Superlattice Engineering with Chemically Precise Molecular Building Blocks.

Correlating nanoscale building blocks with mesoscale superlattices, mimicking metal alloys, a rational engineering strategy becomes critical to generate designed periodicity with emergent properties. For molecule-based superlattices, nevertheless, nonrigid molecular features and multistep self-assembly make the molecule-to-superlattice correlation less straightforward. In addition, single component systems possess intrinsically limited volume asymmetry of self-assembled spherical motifs (also known as "mesoatoms"), further hampering novel superlattices' emergence.

Corner-, edge-, and facet-controlled growth of nanocrystals.

The ability to precisely control nanocrystal (NC) shape and composition is useful in many fields, including catalysis and plasmonics. Seed-mediated strategies have proven effective for preparing a wide variety of structures, but a poor understanding of how to selectively grow corners, edges, and facets has limited the development of a general strategy to control structure evolution. Here, we report a universal synthetic strategy for directing the site-specific growth of anisotropic seeds to prepare a library of designer nanostructures.

Position- and Orientation-Controlled Growth of Wulff-Shaped Colloidal Crystals Engineered with DNA.

Colloidal crystals have emerged as promising candidates for building optical microdevices. Techniques now exist for synthesizing them with control over their nanoscale features (e.g.

Device-quality, reconfigurable metamaterials from shape-directed nanocrystal assembly.

Anchoring nanoscale building blocks, regardless of their shape, into specific arrangements on surfaces presents a significant challenge for the fabrication of next-generation chip-based nanophotonic devices. Current methods to prepare nanocrystal arrays lack the precision, generalizability, and postsynthetic robustness required for the fabrication of device-quality, nanocrystal-based metamaterials [Q. Y.

Colloidal crystal engineering with metal-organic framework nanoparticles and DNA.

Colloidal crystal engineering with nucleic acid-modified nanoparticles is a powerful way for preparing 3D superlattices, which may be useful in many areas, including catalysis, sensing, and photonics. To date, the building blocks studied have been primarily based upon metals, metal oxides, chalcogenide semiconductors, and proteins. Here, we show that metal-organic framework nanoparticles (MOF NPs) densely functionalized with oligonucleotides can be programmed to crystallize into a diverse set of superlattices with well-defined crystal symmetries and compositions.

Yolk-shell nanovesicles endow glutathione-responsive concurrent drug release and T MRI activation for cancer theranostics.

The effort of incorporating therapeutic drugs with imaging agents has been one of the mainstreams of nanomedicine, which holds great promise in cancer treatment in terms of monitoring therapeutic drug activity and evaluating prognostic index. However, it is still technically challenging to develop nanomedicine endowing a spatiotemporally controllable mechanism of drug release and activatable imaging capability. Here, we developed a yolk-shell type of GSH-responsive nanovesicles (NVs) in which therapeutic drug (Doxorubicin, DOX) and magnetic resonance imaging (MRI) contrast agent (ultrasmall paramagnetic iron oxide nanoparticles, USPIO NPs) formed complexes (denoted as USD) and were encapsulated inside the NVs.

Multimetallic High-Index Faceted Heterostructured Nanoparticles.

Multimetallic heterostructured nanoparticles with high-index facets potentially represent an important class of highly efficient catalysts. However, due to their complexity, they are often difficult to synthesize. Herein, a library of heterostructured, multimetallic (Pt, Pd, Rh, and Au) tetrahexahedral nanoparticles was synthesized through alloying/dealloying with Bi in a tube furnace at 900-1000 °C.

Light-Responsive Colloidal Crystals Engineered with DNA.

A novel method for synthesizing and photopatterning colloidal crystals via light-responsive DNA is developed. These crystals are composed of 10-30 nm gold nanoparticles interconnected with azobenzene-modified DNA strands. The photoisomerization of the azobenzene molecules leads to reversible assembly and disassembly of the base-centered cubic (bcc) and face-centered cubic (fcc) crystalline nanoparticle lattices.

Shape regulation of high-index facet nanoparticles by dealloying.

Tetrahexahedral particles (~10 to ~500 nanometers) composed of platinum (Pt), palladium, rhodium, nickel, and cobalt, as well as a library of bimetallic compositions, were synthesized on silicon wafers and on catalytic supports by a ligand-free, solid-state reaction that used trace elements [antimony (Sb), bismuth (Bi), lead, or tellurium] to stabilize high-index facets. Both simulation and experiment confirmed that this method stabilized the {210} planes. A study of the PtSb system showed that the tetrahexahedron shape resulted from the evaporative removal of Sb from the initial alloy-a shape-regulating process fundamentally different from solution-phase, ligand-dependent processes.

Interface and heterostructure design in polyelemental nanoparticles.

Nanomaterials that form as heterostructures have applications in catalysis, plasmonics, and electronics. Multielement nanoparticles can now be synthesized through a variety of routes, but how thermodynamic phases form in such structures and how specific interfaces between them can be designed and synthesized are still poorly understood. We explored how palladium-tin alloys form mixed-composition phases with metals with known but complex miscibilities.