A Facile and Template-Free Method to Prepare Mesoporous Gold Sponge and Its Pore Size Control

A facile, one-step, template-free method is reported to tune β-d-glucose-stabilized Au nanoparticles (NPs) into 3-D network nanowires (NWs) and thus mesoporous gold sponge on a large scale by precise control of the solution pH in aqueous medium at room temperature. The Au NPs appear to undergo sequentially linear aggregation and welding initially, and then, they randomly cross link into self-supporting, three-dimensional networks with time. The mesoporous gold sponge thus formed, on a millimeter to centimeter scale, exhibits high specific surface area (11.9 m²/g) and small pore sizes of 5−30 nm, as well as high thermal stability up to ∼120 °C, above which it undergoes sintering and reorganization into macroporous gold sponge with pore sizes of ∼1−4 μm depending on annealing temperatures but still with mesoporous walls/filaments.