Amorphous CoFePO hollow nanocubes decorated with g-CN quantum dots to achieve efficient electrocatalytic performance in the oxygen evolution reaction.

Simultaneously enriching active sites and enhancing intrinsic activity in a simple way is of great importance for the design of highly active electrocatalysts for the oxygen evolution reaction (OER), but it still faces challenges. Herein, g-CN quantum dot decorated amorphous hollow CoFe bimetallic phosphate nanocubes (a-CoFePO@CNQD) are prepared as an efficient OER electrocatalyst by a simple etching-phosphating process. Research shows that their unique hollow architecture and amorphous structure can help provide generous exposed active sites for OER, and the incorporation of g-CN quantum dots can effectively adjust the electronic structure to improve the intrinsic activity.

Developing a Cobalt Phosphide Catalyst with Combined Cobalt Defects and Phosphorus Vacancies to Boost Oxygen Evolution Reaction.

Defect engineering, by adjusting the surface charge and active sites of CoP catalysts, significantly enhances the efficiency of the oxygen evolution reaction (OER). We have developed a new CoP catalyst that has both cobalt defects and phosphorus vacancies, demonstrating excellent OER performance. Under both basic and acidic media, the catalyst incurs a modest overvoltage, with 238 mV and 249 mV needed, respectively, to attain a current density of 10 mA cm.

N-Doping Induced Lattice Expansion of 1D Template Confined Ultrathin MoS Sheets to Significantly Enhance Lithium Polysulfides Redox Kinetics for Li-S Battery.

Preparing MoS -based materials with reasonable structure and catalytic activity to enhance the sluggish kinetics of lithium polysulfides (LiPSs) conversion is of great significance for Li-S batteries (LSBs) but still remain a challenge. Hence, hollow nanotubes composed of N-doped ultrathin MoS nanosheets (N-MoS NHTs) are fabricated as efficient S hosts for LSBs by using CdS nanorods as a sacrifice template. Characterization and theoretical results show that the template effectively inhibits the excessive growth of MoS sheets, and N doping expands the interlayer spacing and modulates the electronic structure, thus accelerating the mass/electron transfer and enhancing the LiPSs adsorption and transformation.

Engineering Amorphous/Crystalline Ru(OH)/CoFe-Layered Double Hydroxide for Hydrogen Evolution at 1000 mA cm.

For large-scale industrial applications, it is highly desirable to create effective, economical electrocatalysts with long-term stability for the hydrogen evolution reaction (HER) at a large current density. Herein, we report a unique motif with crystalline CoFe-layered hydroxide (CoFe-LDH) nanosheets enclosed by amorphous ruthenium hydroxide (a-Ru(OH)/CoFe-LDH) to realize the efficient hydrogen production at 1000 mA cm, with a low overpotential of 178 mV in alkaline media. During the continuous HER process for 40 h at such a large current density, the potential remains almost constant with only slight fluctuations, indicating good long-term stability.

Cobalt-Carbon nanotubes supported on VO nanorods as sulfur hosts for High-performance Lithium-Sulfur batteries.

Exploring advanced sulfur cathode materials with high catalytic activity to accelerate the slow redox reactions of lithium polysulfides (LiPSs) is of great significance for lithium-sulfur batteries (LSBs). In this study, a coral-like hybrid composed of cobalt nanoparticle-embedded N-doped carbon nanotubes supported by Vanadium (III) oxide (VO) nanorods (Co-CNTs/C @VO) was designed as an efficient sulfur host using a simple annealing process. Characterization combined with electrochemical analysis confirmed that the VO nanorods exhibited enhanced LiPSs adsorption capacity, and the in situ grown short-length Co-CNTs improved electron/mass transport and enhanced the catalytic activity for conversion to LiPSs.

Confined CoS nanocrystals into N/S-Co-doped carbon nanofibers as a chainmail-like electrocatalyst for high-performance lithium-sulfur batteries with high sulfur loading.

Accelerating phase transposition efficiency of lithium polysulfides (LiPSs) to LS and hampering the solution of LiPSs are the keys to stabilizing lithium-sulfur (Li-S) batteries. Hence, the sulfiphilic ultrafine CoS nanoparticles embedded lithiophilic N, S co-doping carbon nanofibers (CoS/NSCNF) are prepared via the dual-template method, which are then used as sulfur host in Li-S batteries. Particularly, the double active sites (CoS and N, S) in CoS/NSCNF are prone to form "Co-S", "Li-O" or "Li-N" bonds, and then simultaneously improving the chemisorption and interface transposition capability of LiPSs.

Crystal Surface Engineering Induced Active Hexagonal Co P-V O for Highly Stable Lithium-Sulfur Batteries.

Purposeful control of the highly active crystal planes is an effective strategy to improve the nanocrystalline catalytic activity. Therefore, Co P nanocrystals with high exposure of (211) lattice plane loaded at 2D hexagonal V O nanosheets (H-Co P-V O ) are designed via the control of morphology. After optimization, this H-Co P-V O boosts the redox kinetics of lithium polysulfides (LiPSs) in lithium-sulfur batteries (LSBs), which is due to the increase of the Co-active sites by exposing more (211) lattice planes of Co P, and the high adsorption and catalysis characteristic of H-Co P-V O for the conversion of LiPSs into LSBs.

yMoO modified amorphous Co(PO) cubes as an efficient bifunctional electrocatalyst for alkaline overall water splitting.

The exploration of efficient bifunctional electrocatalysts for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) under alkaline conditions is an importantway to promote the development of electrolytic water technology. Herein, the reduced graphene oxide-supported MoO modified amorphous cobalt metaphosphate cubes (a-Co(PO)/MoO/rGO) as bifunctional OER/HER catalyst is prepared by anion exchange and phosphating, using the Prussian blue analogue (PBA) as a precursor. The resulting composite exhibits the low overpotentials (η) that of 290 and 50 mV for OER and HER in 1.

Rational Design of the Lotus-Like N-Co VO -Co Heterostructures with Well-Defined Interfaces in Suppressing the Shuttle Effect and Dendrite Growth in Lithium-Sulfur Batteries.

The shuttle effect caused by soluble lithium polysulfides (LiPSs) and intrinsic slow electrochemical transformation from LiPSs to Li S/Li S will induce undesirable cycling performance, which is the primary obstruct limiting the practical applications of lithium-sulfur (Li-S) batteries. Here a convenient method is designed to fabricate the 2D louts-like N-Co VO -Co heterostructures with well-abundant interfaces and oxygen vacancies (V ), endowing the materials with both "sulfiphilic" and "lithiophilic" features. When employed as the modification layer coated on commercial Celgard 2400 separator, the as-prepared N-Co VO -Co/PP with synergistic adsorption-electrocatalysis effects achieves desirable sulfur electrochemistry, thus showing a high initial discharge capacity of 1466.

Amorphous CoP nanoparticle composites with nitrogen-doped hollow carbon nanospheres for synergetic anchoring and catalytic conversion of polysulfides in Li-S batteries.

The commercial viability of Li-S batteries was obstructed by short cycle life and poor capability owing to slow redox kinetics and polysulfide shuttle effect. To tackle these challenges, the amorphous CoP anchored on N-doped carbon nanospheres with hollow porous structures (CoP/HCS) has been synthesized as a superior sulfur host via a facial pyrolysis approach. The debilitating effect would be hampered during the cycling processing resulting from two reasons:(1) the powerful chemical anchoring between unsaturated Co and Li-polysulfides, (2) the remarkable adaption of volume variation originating from the hollow porous architectures.

Fe(III) Ions-Assisted Aniline Polymerization Strategy to Nitrogen-Doped Carbon-Supported Bimetallic CoFeP Nanospheres as Efficient Bifunctional Electrocatalysts toward Overall Water Splitting.

It remains an urgent demand and challenging task to design and fabricate efficient, stable, and inexpensive catalysts toward sustainable electrochemical water splitting for hydrogen production. Herein, we explored the use of Fe(III) ion-assisted aniline polymerization strategy to embed bimetallic CoFeP nanospheres into the nitrogen-doped porous carbon framework (referred CoFeP-NC). The as-prepared CoFeP-NC possesses excellent hydrogen evolution reaction (HER) performance with the small overpotential (η) of 81 mV and 173 mV generated at a current density of 10 mA cm in acidic and alkaline media, respectively.

Advanced Electrocatalysts with Single-Metal-Atom Active Sites.

Electrocatalysts with single metal atoms as active sites have received increasing attention owing to their high atomic utilization efficiency and exotic catalytic activity and selectivity. This review aims to provide a comprehensive summary on the recent development of such single-atom electrocatalysts (SAECs) for various energy-conversion reactions. The discussion starts with an introduction of the different types of SAECs, followed by an overview of the synthetic methodologies to control the atomic dispersion of metal sites and atomically resolved characterization using state-of-the-art microscopic and spectroscopic techniques.

Facile synthesis of carboxymethyl cellulose sulfur quantum dots for live cell imaging and sensitive detection of Cr(VI) and ascorbic acid.

Nowadays the synthesis of stable fluorescent sulfur quantum dots (SQDs) remains a big challenge. Herein, the utilization of carboxymethyl cellulose (CMC) to synthesis of SQDs is reported. Benefiting from the unique composition and structure of CMC macromolecule, the resulted CMC-SQDs simultaneously show high aqueous dispersibility and stability, tunable emission, stable fluorescence and low cytotoxicity, which make them promising for working as a fluorescent probe.

Unravelling the formation mechanism of alkynyl protected gold clusters: a case study of phenylacetylene stabilized Au molecules.

Despite recent progress in the preparation of alkynyl protected Au clusters with molecular purity (e.g., Na[Au(C[triple bond, length as m-dash]CAr), Ar = 3,5-(CF)CH, Au(C[triple bond, length as m-dash]CPh), Au(C[triple bond, length as m-dash]CPh), and Au(C[triple bond, length as m-dash]CAr), Ar = 2-F-CH), the formation mechanism still remains elusive.

N,S-Codoped hierarchical porous carbon spheres embedded with cobalt nanoparticles as efficient bifunctional oxygen electrocatalysts for rechargeable zinc-air batteries.

Rational design and fabrication of cost-effective, efficient bifunctional electrocatalysts is fundamentally important for the air cathode of metal-air batteries. Herein, a Co(ii) ion-driven self-assembly strategy is described for the synthesis of cobalt-based nanostructured transition metal compounds (Co-NTMCs) embedded in nitrogen and sulfur codoped hierarchical porous carbon submicrospheres (Co-NTMCs@NSC), where condensation of thiourea-ethylenediamine-formaldehyde resin (TEFR) is induced by Co(ii) ions which is simultaneously assembled with polydopamine to form a multifunctional precursor through coordinated interaction. The resulting Co-NTMCs@NSC sample comprises abundant hierarchical porous textures, a high content of active cobalt species including the nanoparticles of Co, CoO and amorphous CoS, and a considerable amount of defective structures.

N, S-codoped CNTs supported CoS nanoparticles prepared by using CdS nanorods as sulfur sources and hard templates: An efficient catalyst for reversible oxygen electrocatalysis.

Non-precious efficient bifunctional catalysts towards oxygen reduction/evolution reactions (ORR/OER) are highly desired to enable the widespread application of rechargeable Zn-air batteries (r-ZABs). Herein, Prussian blue analogues (PBA) anchored on CdS nanorods (CdS NRs) pre-coated with polydopamine (PDA) are utilized as precursors to prepare ultrafine CoS nanoparticles supported on N, S-codoped CNTs (CoS@N,S-CNT), where CdS NRs are served as sulfur sources and hard templates. After pyrolysis, the resulting CoS@N,S-CNT-800 shows a high specific surface area of 142.

Hierarchically Porous Carbon Plates Derived from Wood as Bifunctional ORR/OER Electrodes.

Porous carbon electrodes have emerged as important cathode materials for metal-air battery systems. However, most approaches for fabricating porous carbon electrodes from biomass are highly energy inefficient as they require the breaking down of the biomass and its subsequent reconstitution into powder-like carbon. Here, enzymes are explored to effectively hydrolyze the partial cellulose in bulk raw wood to form a large number of nanopores, which helps to maximally expose the inner parts of the raw wood to sufficiently dope nitrogen onto the carbon skeletons during the subsequent pyrolysis process.

Hierarchically Structured Co(OH)/CoPt/N-CN Air Cathodes for Rechargeable Zinc-Air Batteries.

For the realization of the large-scale deployment of rechargeable Zn-air batteries, it is crucial to develop cost-effective, efficient, and stable bifunctional electrocatalysts for both oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). In this work, an integrated electrocatalyst consisting of Co(OH)/CoPt/N-CN was developed to enable both ORR and OER reactions for Zn-air batteries. The hierarchical Co(OH)/CoPt/N-CN electrocatalyst has desirable electrochemical properties, with comparable activity and better durability than commercial Pt/C for ORR and improved activity and long-term stability than commercial IrO catalyst for OER.

Conducting Polymers Crosslinked with Sulfur as Cathode Materials for High-Rate, Ultralong-Life Lithium-Sulfur Batteries.

Low electrical conductivity and a lack of chemical confinement are two major factors that limit the rate performances and cycling stabilities of cathode materials in lithium-sulfur (Li-S) batteries. Herein, sulfur is copolymerized with poly(m-aminothiophenol) (PMAT) nanoplates through inverse vulcanization to form the highly crosslinked copolymer cp(S-PMAT) in which approximately 80 wt % of the feed sulfur is bonded chemically to the thiol groups of PMAT. A cp(S-PMAT)/C-based cathode exhibits a high discharge capacity of 1240 mAh g at 0.

Graphene Composites with Cobalt Sulfide: Efficient Trifunctional Electrocatalysts for Oxygen Reversible Catalysis and Hydrogen Production in the Same Electrolyte.

Nitrogen and sulfur-codoped graphene composites with Co S (NS/rGO-Co) are synthesized by facile thermal annealing of graphene oxides with cobalt nitrate and thiourea in an ammonium atmosphere. Significantly, in 0.1 m KOH aqueous solution the best sample exhibits an oxygen evolution reaction (OER) activity that is superior to that of benchmark RuO catalysts, an oxygen reduction reaction (ORR) activity that is comparable to that of commercial Pt/C, and an overpotential of only -0.

Impacts of interfacial charge transfer on nanoparticle electrocatalytic activity towards oxygen reduction.

Polymer electrolyte membrane fuel cells represent a next-generation power supply technology that may be used in a diverse range of applications. Towards this end, the rational design and engineering of functional nanomaterials as low-cost, high-performance catalysts is of critical significance in the wide-spread commercialization of fuel cell technology. One major bottleneck is the oxygen reduction reaction (ORR) at the cathode.

Bioreduction of Precious Metals by Microorganism: Efficient Gold@N-Doped Carbon Electrocatalysts for the Hydrogen Evolution Reaction.

The uptake of precious metals from electronic waste is of environmental significance and potential commercial value. A facile bioreductive synthesis is described for Au nanoparticles (ca. 20 nm) supported on N-doped carbon (Au@NC), which was derived from Au/Pycnoporus sanguineus cells.

Oxygen reduction catalyzed by gold nanoclusters supported on carbon nanosheets.

Nanocomposites based on p-mercaptobenzoic acid-functionalized gold nanoclusters, Au102(p-MBA)44, and porous carbon nanosheets have been fabricated and employed as highly efficient electrocatalysts for oxygen reduction reaction (ORR). Au102(p-MBA)44 clusters were synthesized via a wet chemical approach, and loaded onto carbon nanosheets. Pyrolysis at elevated temperatures led to effective removal of the thiolate ligands and the formation of uniform nanoparticles supported on the carbon scaffolds.

Graphene-Supported Mesoporous Carbons Prepared with Thermally Removable Templates as Efficient Catalysts for Oxygen Electroreduction.

Graphene-supported mesoporous carbons with rich nitrogen self-doped active sites (N-MC/rGO) are prepared by direct pyrolysis of a graphene-oxide-supported polymer composite embedded with massive, evenly distributed amorphous FeOOH that serve as efficient thermally removable templates. The resulting N-MC/rGO catalysts exhibit high surface areas and apparent electrocatalytic activity for oxygen reduction reaction in alkaline media. Among the series, the sample prepared at 800 °C displays the best performance with a more positive onset potential, higher limiting currents, much higher stability, and stronger poison resistance than commercial Pt/C.

Oxygen electroreduction promoted by quasi oxygen vacancies in metal oxide nanoparticles prepared by photoinduced chlorine doping.

Quasi oxygen-deficient indium tin oxide nanoparticles (ITO NPs) were prepared by photoinduced chlorine doping, and exhibited much enhanced electrocatalytic activity for oxygen reduction reaction (ORR) in alkaline media, as compared with pristine ITO.