Inspired by the unique properties of ultrathin 2D nanomaterials and excellent catalytic activities of noble metal nanostructures for renewable fuel cells, a facile method is reported for the high-yield synthesis of ultrathin 2D PdCu alloy nanosheets under mild conditions. Impressively, the obtained PdCu alloy nanosheet after being treated with ethylenediamine can be used as a highly efficient electrocatalyst for formic acid oxidation. The study implicates that the rational design and controlled synthesis of an ultrathin 2D noble metal alloy may open up new opportunities for enhancing catalytic activities of noble metal nanostructures.

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Synthesis of Ultrathin PdCu Alloy Nanosheets Used as a Highly Efficient Electrocatalyst for Formic Acid Oxidation

The alkaline direct alcohol fuel cell (ADAFC) is an environmentally friendly electrochemical energy source that can drive a plethora of consumer and portable electronics. Research in ADAFCs has continued to attract major attention due to their several advantages over conventional proton-exchange membrane fuel cells (PEMFC); these include the emergence of anion-exchange membranes (AEM), easy handling of liquid alcohol fuels compared to hydrogen, higher volumetric energy densities of alcohols compared to hydrogen, enhanced reaction kinetics of alcohols and oxygen reduction reaction in alkaline media. Further developments in this field are dependent on improving the performance of nanostructured electrocatalysts and AEMs. This review is an overview of some notable advances made in recent years. Importantly, it provides an excellent insight into the fundamental principles that allow for the intelligent design and synthesis of non-precious metal nanostructured electrocatalysts for the cathode and anode reactions of ADAFCs. This review is an attempt to find answers to questions such as “Why should I use a particular catalyst for the ADAFC?”, “What are the underlying principles that must inform my choice in designing such a catalyst?”, and “What synthesis method(s) or catalyst supports should be considered to prepare catalysts with the appropriate physicochemical properties for high-performance?” The knowledge provided in this review can be applied not only to ADAFCs, but also to several other electrocatalytic systems (such as various other fuel cell systems, electrochemical sensors, and metal–air batteries).

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Nanostructured platinum-free electrocatalysts in alkaline direct alcohol fuel cells: catalyst design, principles and applications

Freestanding ultrathin 2D noble metal nanosheets have drawn enormous attention due to their potential applications in various fields. However, the synthesis of 2D noble metal nanosheets still remains a great challenge due to the lack of an intrinsic driving force for anisotropic growth of 2D structures. Here, a facile one-pot synthesis of ultrathin freestanding porous Pd nanosheets (≈2.5 µm in lateral size and 10 nm in thickness) flexibly knitted by interweaved ultrathin nanowires with the assistance of poly(diallyldimethylammonium chloride) is presented. Nanoparticles attachment and subsequent self-assembly in the synthetic process are responsible for the formation of such intriguing nanostructures. Moreover, finely controlling the pH value of the precursor solution leads to yield different Pd nanostructures with tunable dimensionalities, including 3D nanoflowers, 2D nanosheets, and 1D nanochains. Owing to the unique structural features, the obtained freestanding porous Pd nanosheets exhibit excellent electrocatalytic activity and stability towards formic acid oxidation compared to those of other dimensional counterparts and commercial Pd black.

One‐Pot Synthesis of Freestanding Porous Palladium Nanosheets as Highly Efficient Electrocatalysts for Formic Acid Oxidation

Pd–Ag decorated g-C3N4 as an efficient photocatalyst for hydrogen production from water under direct solar light irradiation

Formic acid oxidation is an important electrocatalytic reaction in protonexchange membrane (PEM) fuel cells, in which both active sites and species adsorption/activation play key roles. In this study, we have developed hollow Pd-Ag alloy nanostructures with high active surface areas for application to electrocatalytic formic acid oxidation. When a certain amount of Ag is incorporated into a Pd lattice, which is already a highly active material for formic acid oxidation, the electrocatalytic activity can be significantly boosted. As indicated by theoretical simulations, coupling between Pd and Ag induces polarization charges on Pd catalytic sites, which can enhance the adsorption of HCOO* species. As a result, the designed electrocatalysts can achieve reduced Pd usage and enhanced catalytic properties at the same time. This study represents an approach that simultaneously fabricates hollow structures to increase the number of active sites and utilizes interatomic interactions to tune species adsorption/activation towards improved electrocatalytic performance.

Pd-Ag alloy hollow nanostructures with interatomic charge polarization for enhanced electrocatalytic formic acid oxidation

Polyhedral noble–metal nanocrystals have received much attention and wide applications as electrical and optical devices as well as catalysts. In this work, a straightforward and effective hydrothermal route for the controllable synthesis of the high-quality Pd–Ag alloy polyhedrons with uniform size is presented. The morphology, composition and structure of the Pd–Ag alloy polyhedrons are fully characterized by the various physical techniques, demonstrating the Pd–Ag alloy polyhedrons are highly alloying. The formation/growth mechanisms of the Pd–Ag alloy polyhedrons are explored and discussed based on the experimental observations and discussions. As a preliminary electrochemical application, the Pd–Ag alloy polyhedrons are applied in the formic acid oxidation reaction, which shows higher electrocatalytic activity and stability than commercially available Pd black due to the “synergistic effects” between Pd and Ag atoms.

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Polyhedral Palladium-Silver Alloy Nanocrystals as Highly Active and Stable Electrocatalysts for the Formic Acid Oxidation Reaction.

Nanosized Rh grown on single-walled carbon nanohorns for efficient methanol oxidation reaction

Herein, the conformational switch of G-rich oligonucleotide (GDNA) demonstrated the obvious functional switch of GDNA which was found to significantly affect the fluorescence of the in-situ synthesized DNA/silver nanocluster (DNA-AgNC) in homogeneous solution. We envisioned that the allosteric interaction between GDNA and DNA-AgNC would be possible to be used for screening telomere-binding ligands. A unimolecular probe (12C5TG) is ingeniously designed consisting of three contiguous DNA elements: G-rich telomeric DNA (GDNA) as molecular recognition sequence, T-rich DNA as linker and C-rich DNA as template of DNA-AgNC. The quantum yield and stability of 12C5TG-AgNC is greatly improved because the nearby deoxyguanosines tended to protect DNA/AgNC against oxidation. However, in the presence of ligands, the formation of G-quadruplex obviously quenched the fluorescence of DNA-AgNC. By taking full advantage of intramolecular allosteric effect, telomere-binding ligands were selectively and label-free screened by using deoxyguanines and G-quadruplex as natural fluorescence enhancer and quencher of DNA-AgNC respectively. Therefore, the functional switching of G-rich structure offers a cost-effective, facile and reliable way to screen drugs, which holds a great potential in bioanalysis as well.

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A selective and label-free strategy for rapid screening of telomere-binding Ligands via fluorescence regulation of DNA/silver nanocluster

Is economic crisis an opportunity for realizing the low-carbon transition? A simulation study on the interaction between economic cycle and energy regulation policy

Qi Zhang

Papers

Polyhedral Palladium-Silver Alloy Nanocrystals as Highly Active and Stable Electrocatalysts for the Formic Acid Oxidation Reaction.

Nanosized Rh grown on single-walled carbon nanohorns for efficient methanol oxidation reaction

A selective and label-free strategy for rapid screening of telomere-binding Ligands via fluorescence regulation of DNA/silver nanocluster

Is economic crisis an opportunity for realizing the low-carbon transition? A simulation study on the interaction between economic cycle and energy regulation policy