This paper describes the fabrication and electrochemical behavior of hierarchical nanoporous gold film (HNPGF) electrode by multi-cyclic electrochemical co-alloying/dealloying of two sacrifice metals (Zn and Sn) with gold. Different from the nanoporous gold film (NPGF) formed in the electrolyte of ZnCl2 in benzyl alcohol, the HNPGF obtained possessed special hierarchical porous structure and extra high roughness factor of 1250. This study reveals that hierarchical porous gold film electrodes are promising for catalysis.

Pure rutile nanorods were synthesized by hydrolysis of TiCl4 ethanolic solution in water at 50°C. The assembly of rutile nanorods could be controlled through simply changing the molar ratios of TiCl4, ethanol, and water, resulting in different superstructures with flower-or urchinlike morpholo gies. The resulting samples were characterized with X-ray diffraction, scanning electron microscopy, transmission electron microscopy, highresolution transmission electron microscopy, nitrogen sorption, and UV-vis diffuse reflectance spectrum. A possible mechanism for the growth and assembly of rutile nanorod superstructures was proposed on the basis of characterization results. More importantly, we found that those low temperature synthesized superstructures showed significantly higher photocataly-tic activities than commercial photocatalyst P25 on degradation of rhodamine B in water under artifi-cial solar light. This study provides a simple and inexpensive way to prepare high active rutile nanorods superstructures photocatalysts on a large scale.

Hierarchical porous iron oxide films with different morphologies have for the first time been fabricated through hydrothermal reactions between an iron substrate and iodine powder in water or ethanol, which can be explained by a mechanism analogous to the Kirkendall effect.