Self-assembled PtNi layered metallene nanobowls for pH-universal electrocatalytic hydrogen evolution.

Compared with layered materials such as graphite and transition metal disulfide compounds with highly anisotropic in-plane covalent bonds, it is inherently more challenging to obtain independent metallic two-dimensional films with atomic thickness. In this study, PtNi layered metallene nanobowls (LMBs) with multilayer atomic-scale nanosheets and bowl-like structures have been synthesized in one step using structural and electronic effects. The material has the advantage of catalyzing pH-universal hydrogen evolution reaction (HER). Compared with Pt/C, PtNi LMBs exhibited excellent HER activity and stability under all pH conditions. The overpotentials of 10 mA cm-2 at 0.5 M H2SO4, 1.0 M phosphate buffer and 1.0 M KOH were 14.8, 20.3, and 34.0 mV, respectively. Under acidic, neutral and alkaline conditions, the HER Faraday efficiencies reach 98.97%, 98.85%, and 99.04%, respectively. This study provides an example for the preparation of unique multilayer nanobowls, and also provides a basic research platform for the development of special HER materials.

Distinctive p-d Orbital Hybridization in CuSb Porous Nanonetworks for Enhanced Nitrite Electroreduction to Ammonia.

Electrochemical nitrite reduction reaction ( NO 2 - RR ${\mathrm{NO}}_{\mathrm{2}}^{\mathrm{ - }}{\mathrm{RR}}$ ), as a green and sustainable ammonia synthesis technology, has broad application prospects and environmental friendliness. Herein, an unconventional p-d orbital hybridization strategy is reported to realize the fabrication of defect-rich CuSb porous nanonetwork (CuSb PNs) electrocatalyst for NO 2 - RR ${\mathrm{NO}}_{\mathrm{2}}^ - {\mathrm{RR}}$ . The crystalline/amorphous heterophase structure is cleverly introduced into the porous nanonetworks, and this defect-rich structure exposes more atoms and activated boundaries. CuSb PNs exhibit a large NH3 yield ( r N H 3 ${{r}_{{\mathrm{N}}{{{\mathrm{H}}}_{\mathrm{3}}}}}$ ) of 946.1 µg h-1 m cat - 1 ${\mathrm{m}}_{{\mathrm{cat}}}^{ - {\mathrm{1}}}$ and a high faradaic efficiency (FE) of 90.7%. Experimental and theoretical studies indicate that the excellent performance of CuSb PNs results from the defect-rich porous nanonetworks structure and the p-d hybridization of Cu and Sb elements. This work describes a powerful pathway for the fabrication of p-d orbital hybrid defect-rich porous nanonetworks catalysts, and provides hope for solving the problem of nitrogen oxide pollution in the field of environment and energy.

Metal nanoparticles capped with plant polyphenol for oxygen reduction electrocatalysis.

The development of a convenient and universal strategy for the synthesis of inorganic-organic hybrid nanomaterials with phenolic coating on the surface is of special significance for the preparation of electrocatalysts. In this work, we report an environmentally friendly, practical, and convenient method for one-step reduction and generation of organically capped nanocatalysts using natural polyphenol tannic acid (TA) as reducing agents and coating agents. TA coated metal (Pd, Ag and Au) nanoparticles are prepared by this strategy, among which TA coated Pd nanoparticles (PdTA NPs) show excellent oxygen reduction reaction activity and stability under alkaline conditions. Interestingly, the TA in the outer layer makes PdTA NPs methanol resistant, and TA acts as molecular armor against CO poisoning. We propose an efficient interfacial coordination coating strategy, which opens up new way to regulate the interface engineering of electrocatalysts reasonably and has broad application prospects.

B, P-co-doped PdCu nanothorn assemblies for enhanced oxygen reduction electrolysis.

Nonmetal doping is a promising strategy to improve electrocatalytic performance of noble metal based catalysts for oxygen reduction reaction (ORR). Herein, we report a facile method to fabricate PdCuBP nanothorn assemblies (PdCuBP NTAs) by co-doping B and P into pre-synthesized PdCu NTAs using NaBH4and NaH2PO2as B source and P source, respectively. The metal-nonmetal structure and multi-branched morphology can optimize oxygen adsorption energy and avoid catalyst migration, agglomeration and Ostwald ripening. As such, the obtained PdCuBP NTAs exhibit efficient activity and excellent long-term stability for ORR. This research offers an excellent strategy for co-doping nonmetal elements into metal nanocrystals with controllable composition and structure to improve electrocatalytic ORR performance.

Tannic acid modified PdAu alloy nanowires as efficient oxygen reduction electrocatalysts.

Design of the structure, composition and interface of the catalysts is very important to improve oxygen reduction reaction (ORR) catalytic activity under alkaline environment. Herein, we propose a direct method to rapid synthesis of tannic acid (TA) modified PdAu alloy nanowires (PdAu@TA NWs). Compared with pure PdAu NWs and commercial Pt/C, the PdAu@TA NWs exhibit superior ORR electrocatalytic activity (mass activity: 0.73 A mg-1metaland specific activity: 3.50 mA cm-2), stability, and methanol tolerance in an alkaline medium because PdAu@TA NWs possess sufficient active sites and synergistic effect that can effectively promote the oxygen reduction, inhibit the oxidation of the catalyst and improve the methanol tolerance of the catalyst. This synthetic method is a promising strategy to prepare metallic catalyst with surface functionalization.

Two-Dimensional Heterojunction Electrocatalyst: Au-Bi2Te3 Nanosheets for Electrochemical Ammonia Synthesis.

The design of Au-based materials with good dispersion and more active sites is critical to enhance the catalytic performance of electrochemical ammonia production. Herein, two-dimensional (2D) heterojunction Au-Bi2Te3 nanosheets (Au-Bi2Te3 NSs) are prepared by Au nanoparticles growing on Bi2Te3 nanosheets. Benefiting from the good dispersion of Au nanoparticles and the synergistic effect of the heterojunction composite, Au-Bi2Te3 NSs demonstrate excellent behavior for an ambient nitrogen reduction reaction (NRR). In a 0.1 M Na2SO4 electrolyte (N2-saturated), Au-Bi2Te3 NSs display a high NH3 yield rate of 32.73 µg h-1 mgcat.-1 and a faradic efficiency of 20.39% at -0.4 V. The proposed synthetic method provides a feasible strategy for designing high-performance heterojunction electrocatalysts for electrochemical ammonia synthesis.

Engineering One-Dimensional AuPd Nanospikes for Efficient Electrocatalytic Nitrogen Fixation.

Designing one-dimensional (1D) bimetallic nanomaterials is of great significance for electrochemical nitrogen fixation. Inspired by this, 1D AuPd nanospikes (AuPd NSs) composed with internal Au nanowire and external Pd nanohumps were fabricated by a flexible low-temperature wet-chemical method. Benefiting from the excellent electron transport efficiency of the 1D material and the accessible surface area provided by the unique nanospike-like structure, AuPd NSs exhibit outstanding nitrogen reduction reaction performance with an NH3 yield rate of 16.9 µg h-1 mg-1cat. and a Faradaic efficiency of 15.9% at -0.3 V under 0.1 M Na2SO4. This work not only provides an effective electrocatalyst for nitrogen fixation technology, but also presents a flexible method for the controlled synthesis of spike-like nanomaterials.

Flexible synthesis of Au@Pd core-shell mesoporous nanoflowers for efficient methanol oxidation.

The design of bimetallic core-shell nanostructures with mesoporous surfaces is considered significant to strengthen the catalytic activity and stability for direct methanol fuel cells. Here, we report a flexible method to synthesize Au@Pd core-shell mesoporous nanoflowers (Au@mPd NFs) with Au core coated with mesoporous Pd nano-petals, in which polymeric micelle-assembled structures are used as templates to induce the formation of mesopores. Benefiting from the electronic and structural effects, Au@mPd NFs show excellent electrocatalytic activity and stability for methanol oxidation reaction in alkaline electrolytes. This study demonstrates a versatile strategy for the fabrication of core-shell mesoporous nanoflowers with adjustable composition.

B-Doped PdRu nanopillar assemblies for enhanced formic acid oxidation electrocatalysis.

Adjusting the morphology and composition of Pd-based materials is a promising strategy to improve their performance for the electrocatalytic formic acid oxidation reaction (FAOR). In this work, we report the preparation of B-doped PdRu nanopillar assemblies (B-PdRu NPAs) by a two-step method using NaBH4 as the boron dopant. On combining the hyper-branched structure and the multi-component synergistic effect, B-PdRu NPAs achieve a high mass activity of 1.09 mA µg-1Pd for the FAOR and retain 73.19% of the initial activity after 500 cycles, which is superior to undoped counterparts. The proposed synthesis strategy provides a simple method for the synthesis of metal-nonmetal nanomaterials with desired composition and design structure for electrocatalytic fields.

Binary nonmetal S and P-co-doping into mesoporous PtPd nanocages boosts oxygen reduction electrocatalysis.

The development of doped noble metal catalysts with nonmetal elements to improve the catalytic performance toward the oxygen reduction reaction (ORR) is significant for proton exchange membrane fuel cell technology. Here, we report a one-pot for dual-nonmetal-doping strategy for the synthesis of S and P-co-doped mesoporous PtPd nanocages (PtPdSP mNCs) by using pre-synthesized mesoporous PtPd nanocages (PtPd mNCs) as the precursor and triphenylphosphine sulphide as both S and P sources. Benefitting from the combined advantages of metal-nonmetal incorporation, hollow cavity and surface porosity, the resultant quaternary PtPdSP mNCs exhibit outstanding ORR activity and long-term stability. This research work provides a good strategy for the doping of two or more selected nonmetallic elements into metallic nanocrystals with a controllable structure and composition.

Three-dimensional Pd-Ag-S porous nanosponges for electrocatalytic nitrogen reduction to ammonia.

Electrochemical nitrogen reduction reaction (NRR) provides a facile and sustainable route to synthesize ammonia. The preparation of efficient and high-performance catalysts is one of the most important issues in large-scale applications of the electrochemical synthesis of ammonia. Herein, we have devised a simple method to fabricate three-dimensional palladium-silver-sulphur porous nanosponges (Pd-Ag-S PNSs) under room temperature. The porous network can provide more active sites and accessible channels for the reaction species. The incorporation of sulfur reduces the energy barrier of NRR and promotes the nitrogen hydrogenation to ammonia. Intrinsically, the Pd-Ag-S PNSs demonstrates a superior NRR performance with an NH3 yield of 9.73 µg h-1 mg-1cat. and a faradaic efficiency of 18.41% at -0.2 V, superior to those of the undoped Pd-Ag PNSs. The design of the three-dimensional metallic nanosponges with the doping of nonmetallic elements is a highly valuable strategy for NRR and other electrocatalytic reactions.

Mesoporous Pt@PtM (M = Co, Ni) cage-bell nanostructures toward methanol electro-oxidation.

Rational design of Pt-based nanostructures with a controllable morphology and composition is vital for electrocatalysis. Herein, we demonstrate a dual-template strategy to fabricate well-defined cage-bell nanostructures including a Pt core and a mesoporous PtM (M = Co, Ni) bimetallic shell (Pt@mPtM (M = Co, Ni) CBs). Owing to their unique nanostructure and bimetallic properties, Pt@mPtM (M = Co, Ni) CBs show higher catalytic activity, better durability and stronger CO tolerance for the methanol oxidation reaction than commercial Pt/C. This work provides a general method for convenient preparation of cage-bell nanostructures with a mesoporous bimetallic shell, which have high promising potential for application in electrocatalytic fields.

Boron-Doped PdCuAu Nanospine Assembly as an Efficient Electrocatalyst toward Formic Acid Oxidation.

Control of the composition and morphology of Pd-based electrocatalysts is a promising strategy for the development of efficient direct formic acid fuel cells. Herein, a two-step method is presented for the design of B-doped PdCuAu nanospine assemblies (B-PdCuAu NAs) using NaBH4 as the boron dopant. The boron content can be tailored easily by tuning the reaction time, and an optimal boron content is beneficial to promote the formic acid oxidation reaction. Such B-PdCuAu NAs exhibit superior mass and specific activities to commercial Pd black and PdCuAu NAs in alkaline solution. The excellent catalytic performance of B-PdCuAu NAs may arise from the increase in surface active sites and the electronic effect of boron modification. This work provides a facile synthesis of the B-doped metallic catalysts and highlights the boron modification in improving their performance as anode electrocatalysts for fuel cells.

Mesoporous Au3Pd Film on Ni Foam: A Self-Supported Electrocatalyst for Efficient Synthesis of Ammonia.

As a promising alternative approach to industrial N2 fixation process, electrocatalytic N2 reduction reaction (NRR) can achieve efficient, sustainable, and eco-friendly ammonia production under ambient conditions. Developing efficient NRR catalysts is critical for the electrochemical ammonia synthesis. Herein, self-supported mesoporous Au3Pd film on Ni foam (mAu3Pd/NF) has been in situ synthesized via a micelle-assisted replacement strategy. Combination of bimetallic compositions, interconnected mesoporous structure, and binder-free characteristic, the mAu3Pd/NF shows a superior NRR performance in 0.1 M Na2SO4. This micelle-assisted replacement route is very important to construct efficient self-supporting mesoporous films for the NRR and other fields.

Synergism of Interface and Electronic Effects: Bifunctional N-Doped Ni3 S2 /N-Doped MoS2 Hetero-Nanowires for Efficient Electrocatalytic Overall Water Splitting.

The realization of water electrolysis on the basis of highly active, cost-effective electrocatalysts is significant yet challenging for achieving sustainable hydrogen production from water. Herein, N-doped Ni3 S2 /N-doped MoS2 1D hetero-nanowires supported by Ni foam (N-Ni3 S2 /N-MoS2 /NF) are readily synthesized through a chemical transformation strategy by using NiMoO4 nanowire array growth on Ni foam (NiMoO4 /NF) as the starting material. With the in situ generation of Ni3 S2 /MoS2 heterointerfaces within nanowires and the incorporation of N- anions, an extraordinary hydrophilic nature with abundant, well-exposed active sites and optimal reaction dynamics for both oxidation and reduction of water are obtained. Attributed to these properties, as-converted N-Ni3 S2 /N-MoS2 /NF exhibits highly efficient electrocatalytic activities for both hydrogen and oxygen evolution reactions under alkaline conditions. The superior bifunctional properties of N-Ni3 S2 /N-MoS2 /NF enable it to effectively catalyze the overall water-splitting reaction.

Enhanced Oxygen Reduction and Methanol Oxidation Electrocatalysis over Bifunctional PtPdIr Mesoporous Hollow Nanospheres.

Designing and constructing nano-architectures with abundant reactive atoms exposed on the surface and widely open pore interiors is an effective strategy for highly efficient utilization of Pt-based catalysts. Herein, we report a facile method to synthesize tri-metallic PtPdIr mesoporous hollow nanospheres (PtPdIr MHNSs) by selective chemical removal of sacrificial metallic cores from pre-constructed Pd@PtIr mesoporous nanospheres (Pd@PtIr MNSs). The unique nano-architectures, with mesoporous shells interconnected into the interior hollow cavities and the synergistic electronic effect from tri-metallic PtPdIr composition, enable the as-synthesized PtPdIr MHNSs to be efficient bifunctional electrocatalysts for catalyzing both methanol oxidation reaction (MOR) and oxygen reduction reaction (ORR).

All-metallic nanorattles consisting of a Pt core and a mesoporous PtPd shell for enhanced electrocatalysis.

The fabrication of nanorattles with controllable compositions and structures is very important for catalytic applications. Herein, we propose a facile method for synthesis of very unique all-metallic nanorattle consisting of a Pt core and a mesoporous PtPd shell (named Pt@mPtPd). Owing to its spatially and locally separated active inner Pt core and mesoporous PtPd shell, the Pt@mPtPd nanorattle shows the enhanced performance for oxygen reduction reaction. The newly designed Pt@mPtPd nanorattle is quite different from traditional nanorattles with porous carbon and silica shell in its catalytically functional mesoporous metallic shell. The proposed facile method is highly valuable for the design of all-metallic nanorattle with controllable compositions and desired functions.

Interface engineering of Ni5P2 nanoparticles and a mesoporous PtRu film heterostructure on Ni foam for enhanced hydrogen evolution.

Engineering of multicomponent heterostructures can yield exceptional functionalities and enhance electrocatalytic activities by a synergistic effect. Herein, Ni5P2 nanoparticle-decorated mesoporous PtRu film on Ni foam (Ni5P2-mPtRu/NF) has been synthesized via a facile two-step strategy. Ni5P2-mPtRu/NF possesses a well-developed continuous mesoporous structure and strong electronic interaction between Ni5P2 and PtRu, exhibiting an enhanced electrocatalytic performance towards an alkaline hydrogen evolution reaction (HER). Ni5P2-mPtRu/NF achieves a current density of 10 mA cm-2 at an overpotential of 28.8 mV and a low Tafel slope of 56.5 mV dec-1, and has excellent durability. This work provides a promising pathway for developing self-supported mesoporous multicomponent heterostructures as efficient electrocatalysts for an alkaline HER.

Hollow PtPd Nanorods with Mesoporous Shells as an Efficient Electrocatalyst for the Methanol-Oxidation Reaction.

Tailoring the morphology and composition of platinum-based electrocatalysts is of significant importance for the development of highly efficient direct methanol fuel cells. Herein, we report a dual-templating method for the design of hollow PtPd nanorods with mesoporous shells (mPtPd HNRs). We found that F127 micelles favored the formation of mesoporous structures and that SiO2 nanorods served as a hard template for the creation of cavities. The well-developed mesopores, hollow structures, and bimetallic composition of the mPtPd HNRs afforded a sufficient number of active sites to facilitate the electrochemical oxidation of methanol, thereby leading to enhanced activity and stability. This strategy allowed for the reliable preparation of mesoporous hollow platinum-based electrocatalysts with desired compositions and morphologies for catalytic applications.

Ultralong Ternary PtRuTe Mesoporous Nanotubes Fabricated by Micelle Assembly with a Self-Sacrificial Template.

High surface area and fast mass transport rate are important to enhance the activity and stability of catalysts. In this work, tellurium nanowires and F127 triblock copolymer are used as self-sacrificial and soft templates, respectively, to synthesize PtRuTe mesoporous nanotubes (MNTs). The designed PtRuTe MNTs show uniformly distributed mesopores and an internally hollow structure, which can effectively improve Pt utilization, the catalytic activity and durability, and CO tolerance for the methanol oxidation reaction. Very different from previous 1D metallic catalysts with solid interiors and smooth surfaces, PtRuTe MNTs are unique, with a mesoporous exterior and hollow interior. The facile route presented herein is very feasible for fabricating 1D mesoporous metallic catalysts.