The design and synthesis of highly active oxygen reduction reaction (ORR) catalysts with strong durability at low cost is extremely desirable but still remains a significant challenge. Here we develop an efficient strategy that utilizes organopalladium(I) complexes containing palladium-palladium bonds as precursors for the synthesis of strongly coupled Pd tetrahedron-tungsten oxide nanosheet hybrids (Pd/W18O49) to improve the electrocatalytic activity and stability of Pd nanocrystals. The hybrid materials are synthesized by direct nucleation, growth, and anchoring of Pd tetrahedral nanocrystals on the in situ-synthesized W18O49 nanosheets. Compared to supportless Pd nanocrystals and W18O49, their hybrids exhibited not only surprisingly high activity but also superior stability to Pt for the ORR in alkaline solutions. X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, and electrochemical analyses indicated that the enhanced electrocatalytic activity and durability are associated with the increased number and improved catalytic activity of active sites, which is induced by the strong interaction between the Pd tetrahedrons and W18O49 nanosheet supports. The present study provides a novel strategy for synthesizing hybrid catalysts with strong chemical attachment and electrical coupling between nanocatalysts and supports. The strategy is expected to open up exciting opportunities for developing a novel class of metal-support hybrid nanoelectrocatalysts with improved ORR activity and durability for both fuel cells and metal-air batteries.

This review highlights the synthesis and optical properties of carbon quantum dots and their application in metal ion sensing.

Fluorescent carbon dots prepared by a heat treatment of ethylene glycol solution can act as fluorescence turn-on probes for sensitive and selective detection of Ag+ ions.

The electrochemical production of H2O2 from O2 catalyzed by [Au25(SC12H25)18] was studied as a function of the charge state (-1, 0 and +1). Maximum H2O2 production (∼90%) was obtained from the negatively charged clusters (Au25(-)) due to the efficient electron transfer from the anionic Au25(-) cluster into the LUMO (π*) of O2.

To obtain stable and ultrafine Pt nanoclusters, a trigonal prismatic coordination cage with the sulfur atoms on the edges was solvothermally synthesized to confine them. In the structure of {Ni(TC4A-SO)(TDC) (HO)} (HTC4A-SO = p-tert-butylsulfonylcalix[4]arene; HTDC = 2,5-thiophenedicarboxylic acid), three Ni-(TC4A-SO) SBUs are bridged by three TDC ligands into a triangle and two such triangles are pillared by three pairs of TDC ligands to form a trigonal prism. The cage cavity has 12 sulfur atoms on the surface. Because of the porous structure and strong covalent interaction between metal and sulfur, ultrafine Pt nanoclusters composed of less than ∼18 Pt atoms can be facilely confined in the present trigonal prismatic cage (Pt@CIAC-121). The as-synthesized Pt NCs exhibit higher electrocatalytic activity than commercial Pt/C toward hydrogen evolution reaction.

A honeycomb-type structured Na3V2(PO4)3/C microball with hierarchical pores and 3D conductive network exhibits enhanced sodium intercalation kinetics and superior electrochemical properties.

We report here a one-pot synthesis of sub-nanometer sized copper clusters capped with a water-soluble ligand, L-glutathione (SGH), through a chemical reduction process. The composition of the as-prepared Cu 6 (SG) 3 nanoclusters was confirmed by electrospray ionization mass spectrometry (ESI-MS) and matrixassisted laser desorption ionization time-of-flight mass spectroscopy (MALDI-TOF MS). The FTIR, 1 H NMR and XPS characterization methods showed that with the production of Cu 6 (SG) 3 clusters and the formation of Cu-S bonds, the surface chemical environment of the clusters exhibited a significant change. The produced water-soluble clusters show aggregation-induced fluorescence upon the addition of ethanol into the cluster aqueous solution. By loading on the TiO 2 support, the as-prepared copper nanoclusters were successfully applied to the electrochemical detection of glucose. Compared to large Cu nanoparticles, the Cu 6 (SG) 3 nanoclusters exhibited higher sensitivity and a wider linear range for glucose detection.

Kong for helpful comments and suggestions. Xiaohui Gao gratefully acknowledge the research support from the Faculty of Business and Economics at the University of Hong Kong and the Research Grants Council of the Hong Kong SAR government. Special thanks to Xiaoding Liu for research assistance.