Reduction effect of pore wall and formation of Au nanowires inside monolithic mesoporous silica

This Letter reported reduction effect of pore wall on AuCl4− ions at low temperature (<100 °C) and formation of Au nanowires within pores of monolithic mesoporous silica. Such nanostructured Au/silica assembly was obtained by soaking the silica into HAuCl4 solution, drying and annealing at ⩽300 °C, without any special reduction treatment. Further experiments, revealed that the reducing groups OH on pore walls are responsible for reduction of Au3+ ions at low temperature. The formation of Au nanowires can be attributed to the low nucleation rate, uni-directional diffusion of Au atoms along pore channels and the size confinement of pore channels.