Coupling Single-Atom Sites and Ordered Intermetallic PtM Nanoparticles for Efficient Catalysis in Fuel Cells.

The design of an efficient catalytic system with low Pt loading and excellent stability for the acidic oxygen reduction reaction is still a challenge for the extensive application of proton-exchange membrane fuel cells. Here, a gas-phase ordered alloying strategy is proposed to construct an effective synergistic catalytic system that blends PtM intermetallic compounds (PtM IMC, M = Fe, Cu, and Ni) and dense isolated transition metal sites (M-N ) on nitrogen-doped carbon (NC). This strategy enables Pt nanoparticles and defects on the NC support to timely trap flowing metal salt without partial aggregation, which is attributed to the good diffusivity of gaseous transition metal salts with low boiling points.

Multicarbons generation factory: CuO/Ni single atoms tandem catalyst for boosting the productivity of CO electrocatalysis.

Tandem electrocatalysis is an emerging concept for effective electrochemical CO reduction reaction (CORR) towards multicarbons (C). This decouples the multiple steps of CO-to-C into two steps of CO-to-CO and CO-to-C catalyzed by individual catalysts, to improve the Faradic efficiency (FE). However, due to the mass-transport limitation of CO from the generation site to the long-distance consumption site, such a strategy still remains challenge for high-rate production of C products.

Dual confinement of high-loading enzymes within metal-organic frameworks for glucose sensor with enhanced cascade biocatalysis.

The intrinsically fragile nature and leakage of the enzymes is a major obstacle for the commercial sensor of a continuous glucose monitoring system. Herein, a dual confinement effect is developed in a three dimensional (3D) nanocage-based zeolite imidazole framework (NC-ZIF), during which the high-loading enzymes can be well encapsulated with unusual bioactivity and stability. The shell of NC-ZIF sets the first confinement to prevent enzymes leakage, and the interior nanocage of NC-ZIF provides second confinement to immobilize enzymes and offers a spacious environment to maintain their conformational freedom.

Integrating single-cobalt-site and electric field of boron nitride in dechlorination electrocatalysts by bioinspired design.

The construction of enzyme-inspired artificial catalysts with enzyme-like active sites and microenvironment remains a great challenge. Herein, we report a single-atomic-site Co catalyst supported by carbon doped boron nitride (BCN) with locally polarized B-N bonds (Co SAs/BCN) to simulate the reductive dehalogenases. Density functional theory analysis suggests that the BCN supports, featured with ionic characteristics, provide additional electric field effect compared with graphitic carbon or N-doped carbon (CN), which could facilitate the adsorption of polarized organochlorides.

Construction of highly accessible single Co site catalyst for glucose detection.

The development of high-performance glucose sensors is an urgent need, especially for diabetes mellitus diagnosis. However, the glucose monitoring is conventionally operated in an invasive finger-prick manner and their noninvasive alternatives largely suffered from the relatively poor sensitivity, selectivity, and stability, resulted from the lack of robust and efficient catalysts. In this paper, we design a concave shaped nitrogen-doped carbon framework embellished with single Co site catalyst (Co SSC) by selectively controlling the etching rate on different facet of carbon substrate, which is beneficial to the diffusion and contact of analyte.

Coplanar Pt/C Nanomeshes with Ultrastable Oxygen Reduction Performance in Fuel Cells.

Developing highly stable and efficient catalysts toward the oxygen reduction reaction is important for the long-term operation in proton exchange membrane fuel cells. Reported herein is a facile synthesis of two-dimensional coplanar Pt-carbon nanomeshes (NMs) that are composed of highly distorted Pt networks (neck width of 2.05±0.

In Situ Topotactic Transformation of an Interstitial Alloy for CO Electroreduction.

Electrochemical reduction of CO to value-added products holds promise for storage of energy from renewable sources. Copper can convert CO into multi-carbon (C ) products during CO electroreduction. However, developing a Cu electrocatalyst with a high selectivity for CO reduction and desirable production rates for C products remains challenging.

2D PbS Nanosheets with Zigzag Edges for Efficient CO Photoconversion.

The rational design of transition-metal sulfide with two-dimensional (2D) structure and tunable edges on the nanoscale can effectively improve their activity for variously catalytic reactions. Herein, the 2D PbS nanosheets with abundant zigzag edges (e-PbS NS), which exhibited an excellent performance for CO photoconversion to CO, were constructed. The zigzag edges on the PbS NS are beneficial for exposing more active sites and promoting charge separation, thereby accelerating the kinetics process of CO photoreduction.

Single Iron Site Nanozyme for Ultrasensitive Glucose Detection.

Nanomaterials with enzyme-mimicking characteristics have engaged great awareness in various fields owing to their comparative low cost, high stability, and large-scale preparation. However, the wide application of nanozymes is seriously restricted by the relatively low catalytic activity and poor specificity, primarily because of the inhomogeneous catalytic sites and unclear catalytic mechanisms. Herein, a support-sacrificed strategy is demonstrated to prepare a single iron site nanozyme (Fe SSN) dispersed on the porous N-doped carbon.

Room-Temperature Synthesis of Single Iron Site by Electrofiltration for Photoreduction of CO into Tunable Syngas.

Developing a convenient and effective method to prepare single-atom catalysts at mild synthetic conditions remains a challenging task. Herein, a voltage-gauged electrofiltration method was demonstrated to synthesize single-atom site catalysts at room temperature. Under regulation of the graphene oxide membrane, a bulk Fe plate was directly converted into Fe single atoms, and the diffusion rate of Fe ions was greatly reduced, resulting in an ultralow concentration of Fe around the working electrode, which successfully prevented the growing of nuclei and aggregating of metal atoms.

Recover the activity of sintered supported catalysts by nitrogen-doped carbon atomization.

The sintering of supported metal nanoparticles is a major route to the deactivation of industrial heterogeneous catalysts, which largely increase the cost and decrease the productivity. Here, we discover that supported palladium/gold/platinum nanoparticles distributed at the interface of oxide supports and nitrogen-doped carbon shells would undergo an unexpected nitrogen-doped carbon atomization process against the sintering at high temperatures, during which the nanoparticles can be transformed into more active atomic species. The in situ transmission electron microscopy images reveal the abundant nitrogen defects in carbon shells provide atomic diffusion sites for the mobile atomistic palladium species detached from the palladium nanoparticles.

A Supported Nickel Catalyst Stabilized by a Surface Digging Effect for Efficient Methane Oxidation.

A surface digging effect of supported Ni NPs on an amorphous N-doped carbon is described, during which the surface-loaded Ni NPs would etch and sink into the underneath carbon support to prevent sintering. This process is driven by the strong coordination interaction between the surface Ni atoms and N-rich defects. In the aim of activation of C-H bonds for methane oxidation, those sinking Ni NPs could be further transformed into thermodynamically stable and active metal-defect sites within the as-generated surface holes by simply elevating the temperature.

Ambient Synthesis of Single-Atom Catalysts from Bulk Metal via Trapping of Atoms by Surface Dangling Bonds.

Single-atom catalysts (SACs) feature the maximum atom economy and superior performance for various catalysis fields, attracting tremendous attention in materials science. However, conventional synthesis of SACs involves high energy consumption at high temperature, complicated procedures, a massive waste of metal species, and poor yields, greatly impeding their development. Herein, a facile dangling bond trapping strategy to construct SACs under ambient conditions from easily accessible bulk metals (such as Fe, Co, Ni, and Cu) is presented.

Directly transforming copper (I) oxide bulk into isolated single-atom copper sites catalyst through gas-transport approach.

Single-atom metal catalysts have sparked tremendous attention, but direct transformation of cheap and easily obtainable bulk metal oxide into single atoms is still a great challenge. Here we report a facile and versatile gas-transport strategy to synthesize isolated single-atom copper sites (Cu ISAS/NC) catalyst at gram levels. Commercial copper (I) oxide powder is sublimated as mobile vapor at nearly melting temperature (1500 K) and subsequently can be trapped and reduced by the defect-rich nitrogen-doped carbon (NC), forming the isolated copper sites catalyst.

Two-Step Carbothermal Welding To Access Atomically Dispersed Pd on Three-Dimensional Zirconia Nanonet for Direct Indole Synthesis.

Herein, we report a novel carbothermal welding strategy to prepare atomically dispersed Pd sites anchored on a three-dimensional (3D) ZrO nanonet (Pd@ZrO) via two-step pyrolysis, which were evolved from isolated Pd sites anchored on linker-derived nitrogen-doped carbon (Pd@NC/ZrO). First, the NH-HBDC linkers and Zr-based [Zr(μ-O)(μ-OH)] nodes of UiO-66-NH were transformed into amorphous N-doped carbon skeletons (NC) and ZrO nanoclusters under an argon atmosphere, respectively. The NC supports can simultaneously reduce and anchor the Pd sites, forming isolated Pd-N/C sites.

Thermal Emitting Strategy to Synthesize Atomically Dispersed Pt Metal Sites from Bulk Pt Metal.

Developing a facile route to access active and well-defined single atom sites catalysts has been a major area of focus for single atoms catalysts (SACs). Herein, we demonstrate a simple approach to generate atomically dispersed platinum via a thermal emitting method using bulk Pt metal as a precursor, significantly simplifying synthesis routes and minimizing synthesis costs. The ammonia produced by pyrolysis of Dicyandiamide can coordinate with platinum atoms by strong coordination effect.

Trifunctional Self-Supporting Cobalt-Embedded Carbon Nanotube Films for ORR, OER, and HER Triggered by Solid Diffusion from Bulk Metal.

The development of robust and efficient trifunctional catalysts for oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen reaction (HER) is central to regenerative metal-air batteries and overall water splitting. It is still a big challenge to achieve an efficient integration of three functions in one freestanding electrode. Herein, a facile and upscalable strategy is demonstrated, to construct cobalt nanoparticle-encapsulated 3D conductive films (Co/CNFs), which were induced by in situ solid diffusion from bulk cobalt metal.

Unraveling the enzyme-like activity of heterogeneous single atom catalyst.

Herein, we report a heterogeneous single iron atom catalyst exhibiting excellent peroxidase, oxidase and catalase enzyme-like activities (defined as single atom enzymes, SAEs), exceeding those of Fe3O4 nanozymes by a factor of 40. Our findings open up a new family of artificial materials that mimic natural enzymes.