Hierarchically Templated Synthesis of Hollow Nanoporous Gold Rods and TiO₂‐Coated Gold Rods

Abstract Gold nanomaterials have shown promising applications in catalysis and sensing. Among the current directions in the research and development of gold catalysts, the exploration of new forms is one of the major priorities. Using bacteria as the supporting template and polystyrene spheres as the pore‐generation template, a hierarchical‐template synthesis strategy was developed in the present study to synthesize hollow nanoporous gold rods. The pore size can be easily adjusted by using polystyrene spheres (PSS) with different diameters as the template (the pore size is about 160 nm and 70 nm when using 200 nm and 110 nm PSS, respectively, as the template). Moreover, with the simple sol–gel method, different amounts of TiO₂ can be coated on these nanoporous gold rods. The results showed the thermal stability and catalytic activity of the nanoporous gold rods were improved dramatically with moderate TiO₂ coating. Using reduction of 4‐nitrophenol to 4‐aminophenol with sodium borohydride as the model reaction, excellent catalytic properties (reaction rate constant k=0.246 min⁻¹) of the prepared TiO₂‐coated gold rods catalysts were confirmed.