Junhua Song

Efficient Synthesis of MCu (M = Pd, Pt, and Au) Aerogels with Accelerated Gelation Kinetics and their High Electrocatalytic Activity

To accelerate hydrogel formation and further simplify the synthetic procedure, a series of MCu (M = Pd, Pt, and Au) bimetallic aerogels is synthesized from the in situ reduction of metal precursors through enhancement of the gelation kinetics at elevated temperature. Moreover, the resultant PdCu aerogel with ultrathin nanowire networks exhibits excellent electrocatalytic performance toward ethanol oxidation, holding promise in fuel-cell applications.

Self-Assembled Fe-N-Doped Carbon Nanotube Aerogels with Single-Atom Catalyst Feature as High-Efficiency Oxygen Reduction Electrocatalysts

Self-assembled M-N-doped carbon nanotube aerogels with single-atom catalyst feature are for the first time reported through one-step hydrothermal route and subsequent facile annealing treatment. By taking advantage of the porous nanostructures, 1D nanotubes as well as single-atom catalyst feature, the resultant Fe-N-doped carbon nanotube aerogels exhibit excellent oxygen reduction reaction electrocatalytic performance even better than commercial Pt/C in alkaline solution.

Optimization of cobalt/nitrogen embedded carbon nanotubes as an efficient bifunctional oxygen electrode for rechargeable zinc–air batteries

The design of efficient, durable and affordable catalysts for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is indispensable in regenerative energy conversion and storage systems, such as water splitting, fuel cells and rechargeable metal–air batteries. Here we present a high-performance bifunctional catalyst with cobalt and nitrogen embedded carbon nanotubes (CNCNs), which exhibits high electrocatalytic activity towards the ORR and OER. For comparison, iron and nickel embedded carbon nanotubes (FeNCNs and NiNCNs) are also investigated to reveal the electrochemical performance upon transition metal doping. In the half-cell testing, FeNCN-44 and CNCN-100 show better electrochemical activities towards the ORR, while the compositionally optimized CNCN-44 outperforms other prepared catalysts during the OER including commercial RuO2 and Pt/C. The CNCN-44 exhibits a low oxidation overpotential of 0.38 V and stability with negligible deactivation over extended operation, which make it the best catalyst in overall bifunctional performance. We also test the suitability and durability of CNCN-44 as the oxygen electrode for rechargeable Zn–air batteries. The homemade battery exhibits a high open-circuit potential of 1.45 V and stable charge–discharge durability over 12 hours in 6 M KOH electrolyte at 10 mA cm−2, which make our compositionally optimized CNCN-44 a promising candidate as a cathode material for rechargeable zinc–air batteries.

Drug-Derived Bright and Color-Tunable N-Doped Carbon Dots for Cell Imaging and Sensitive Detection of Fe3+ in Living Cells

Inspired by the diverse drug compounds with various heteroatoms (such as N, S, and P) in the drug library, facile synthesis of a new kind of bright and color-tunable N-doped carbon dots (NCDs) has been reported by using a popular antibiotic-aminosalicylic acid-as precursor. The N doping of CDs not only enable great improvement of photoluminescence (PL) efficiency and tunability of PL emission, but also enrich surface functional groups to broaden its application. The as-prepared NCDs possess tunable PL and show a quantum yield of 16.4%, which is the result of PL improvement effect of introduced nitrogen atoms among CDs. The cellular toxicity on H1299 cancer cells indicates that the NCDs have negligible cytotoxicity, excellent biocompatibility, and great resistance to photobleaching. Moreover, the drug-derived NCDs showed excellent sensitivity in detection of Fe3+ in living cells, which indicates the potential application in diagnosis and related biological study.

PdCuPt Nanocrystals with Multibranches for Enzyme-Free Glucose Detection

By carefully controlling the synthesis condition, branched PtCu bimetallic templates were synthesized in aqueous solution. After the galvanic replacement reaction between PtCu templates and the Pt precursors, PdCuPt trimetallic nanocrystals with branched structures were obtained. Owing to the open structure and the optimized composition, the electrochemical experimental results reveal that the PdCuPt trimetallic nanocrystals possess high electrocatalytic activity, selectivity and stability for the oxidation of glucose in alkaline solution. In detail, a detection limit of 1.29 μM and a sensitivity of 378 μA/mM/cm(2) are achieved. The good electrocatalytic performance should be attributed to the unique branched nanostructure as well as the synergistic effect among metals. The superior catalytic properties suggest that these nanocrystals are promising for enzyme-free detection of glucose.

Three-dimensional PtNi hollow nanochains as an enhanced electrocatalyst for the oxygen reduction reaction

Three-dimensional porous PtNi hollow nanochains were successfully synthesized via a galvanic replacement method using Ni nanosponges as sacrificial templates in an aqueous solution. It is found that the composition and shell thickness of 3D PtNi hollow nanochains can be easily controlled by tuning the concentration of Pt precursors. The as-prepared PtNi hollow nanochains with an optimized composition present a high electrochemical surface area (70.8 m2 g−1), which is close to that of commercial Pt/C (83 m2 g−1). Moreover, the PtNi catalyst with a Pt content of ∼77% presents superior electrocatalytic performance for the oxygen reduction reaction compared to commercial Pt/C. It shows a mass activity of 0.58 A mgPt−1, which is around 3 times higher than that of Pt/C. This strategy may be extended to the preparation of other multimetallic nanocrystals with 3D hollow nanostructures, which are expected to present high catalytic properties.

Multifunctional SnO2/3D graphene hybrid materials for sodium-ion and lithium-ion batteries with excellent rate capability and long cycle life

SnO2 is a promising material for both Li-ion and Na-ion batteries owing to its high theoretical capacities. Unfortunately, the electrochemical performance of SnO2 is unsatisfactory because of the large volume change that occurs during cycling, low electronic conductivity of inactive oxide matrix, and poor kinetics, which are particularly severe in Na-ion batteries. Herein, ultra-fine SnO2 nanocrystals anchored on a unique three-dimensional (3D) porous reduced graphene oxide (rGO) matrix are described as promising bifunctional electrodes for Li-ion and Na-ion batteries with excellent rate capability and long cycle life. Ultra-fine SnO2 nanocrystals of size ∼6 nm are well-coordinated to the graphene sheets that comprise the 3D macro-porous structure. Notably, superior rate capability was obtained up to 3 C (1/n C is a measure of the rate that allows the cell to be charged/discharged in n h) for both batteries. In situ X-ray diffractometry measurements during lithiation (or sodiation) and delithiation (or desodiation) were combined with various electrochemical techniques to reveal the real-time phase evolution. This critical information was linked with the internal resistance, ion diffusivity (

Kinetically Controlled Synthesis of Pt-Based One-Dimensional Hierarchically Porous Nanostructures with Large Mesopores as Highly Efficient ORR Catalysts

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