What dictates which ion, I- or Br-, mediates the growth of cubic Pd nanocrystals?

Cubic Pd nanocrystals (CPNCs) as one of typical nanostructures are generally fabricated using I- or Br- as capping ions. However, which ion, I- or Br-, exclusively mediates the growth of CPNCs in a given reaction system is not well understood. Herein, regardless of I- or Br- as the capping ion, we successfully achieved CPNCs in the same reaction system simply by adjusting the pH. Based on the Finke-Watzky kinetic model, an increase in pH accelerates the overall reduction rate of Pd2+, and the formation of CPNCs only occurs over the range of specific solution reduction rate constants (k1). This kinetically illuminates that the reduction rate of Pd2+ is the physicochemical parameter that determines which ion, I- or Br-, dictates the growth of CPNCs. Also, density functional theory (DFT) calculations further elucidate the dependence of the reduction rate of Pd2+ on pH and the configuration of the activated Pd2+ complex.

Synthesis, characterization and photocatalytic properties of In2.77S4/Ti3C2 composites.

Recently, the problem of water pollution, caused by antibiotics, is becoming more and more serious. Photocatalysis is one of the promising technologies for removing antibiotics from water. Herein, the In2.77S4/Ti3C2 composites were prepared by an in-situ hydrothermal growth method for photocatalytic degradation of tetracycline (TC). The as-developed composites were characterized by various methods. The UV-Vis DRS spectra reveals that the introduction of Ti3C2 makes the bandgap of the as-prepared composites smaller and the visible light absorption ability improved. The photocatalytic degradation efficiency of the as-prepared composite is enhanced under visible light illumination. It is shown as first increasing and then decreasing with increasing the content of Ti3C2 in the composite and reaches to the maximum of 89.3% in 90 min, which is higher than 75.1% of In2.77S4 and 6.7% of Ti3C2. The reason of improvement is the interface between In2.77S4 and Ti3C2 is tightly combined to form a heterojunction. Moreover, the photocurrent intensity of the as-obtained composite is improved, while its Nyquist arc radius is decreased. In addition, holes are the main active species and ·OH and ·O2 - play an auxiliary role during the degradation of TC.

Serrated Au/Pd Core/Shell Nanowires with Jagged Edges for Boosting Liquid Fuel Electrooxidation.

Integration of 1D, core/shell, and jagged features into one entity may provide a promising avenue for further enhancing catalyst performance. However, designing such unique nanostructures is extremely challenging. Herein, 1D serrated Au/Pd core/shell nanowires (CSNWs) with jagged edges were produced simply by a one-pot, dual-capping-agent-assisted method involving co-reduction, galvanic replacement, directional coalescence of preformed nanoparticles, and site-selective epitaxial growth of Pd. Au/PdCSNWs, compared with the commercially available Pd/C, exhibited enhanced electrocatalytic performance towards liquid fuel oxidation because of the synergistic effect of the electronic structure and low-coordinated jagged edges.

Cubic superstructures composed of PtPd alloy nanocubes and their enhanced electrocatalysis for methanol oxidation.

Three-dimensional (3D) cubic superstructures of PtPd nanocubes were achieved by spontaneous adjustment of PtIV reduction kinetics, and exhibited enhanced catalytic activity and long-term durability towards methanol oxidation compared with the state-of-the-art Pt/C. This work demonstrates the first example of designing 3D shaped architectures of PtPd nanocubes for methanol electrooxidation.