Freestanding monolayered nanoporous gold films with high electrocatalytic activity via interfacial self-assembly and overgrowth

Abstract

Nanoporous gold freestanding films (NPG FSFs) have been fabricated via overgrowth of gold onto selfassembled monolayers of gold nanocrystals at planar fluid-fluid interfaces. The resulting NPG FSFs are ligand-free on their surfaces and their sizes can be as large as several cm 2 . The NPG FSFs are fairly mechanically robust; their effective Young's moduli are of the order of about 10 GPa. The NPG FSFs exhibit efficient electrocatalytic activity for methanol oxidation with an excellent electrochemical endurance, which is attributed to the presence of high-index facets on the curved surfaces of gold ligaments in the NPG FSFs. It is found that the catalytic performance of as-prepared NPG FSFs is related to the curved-to-flat surface area ratios of gold ligaments in NPG FSFs. The highly curved surface areas in the NPG FSFs can be increased via optimizing the concentration of HAuCl 4 and the citrate to HAuCl 4 molar ratio in the electroless plating solution.

Engineering the internal surfaces of three-dimensional nanoporous catalysts by surfactant-modified dealloying

“…The CA curves show that the current density of Py-NPG is noticeably higher than that of Na 3 CA-NPG and C-NPG in the entire testing period. It is worth noting that Py-NPG exhibits the highest specific current density among reported Au catalysts, including trisoctahedral gold nanoparticles (178 µA cm −2 ) 40 , hollow nanoporous gold nanoparticles (117 µA cm −2 ) 39 , branched Au nanostructures (103 µA cm −2 ) 41 , nanoporous gold film (103 µA cm −2 ) 42 , and spherical Au nanoparticles (65 µA cm −2 ) 42 , for MOR under the same experimental conditions. Since the catalytic activities of NPG also depend on pore sizes 17 , 18 , to clarify possible pore size effect in the high catalysis of Py-NPG, we prepared two additional C-NPG samples with smaller pore sizes of 11.2 (C-NPG 11 ) and 17.1 nm (C-NPG 17 ) to test the catalytic activities (Supplementary Fig.…”

Nanoporous gold film: fabrication and role as a catalytic reactor

“…1 It is attractive due to its high catalytic activity even when the featured length of ligaments is larger than 30 nm. [8][9][10] Among these materials, thin films are more attractive in the catalytic field from an applied and economical point of view. [3][4][5] In the last few years, various NPG materials (film, foam and sponge) have been prepared successfully by dealloying, 6 templating 7 as well as other techniques.…”

Light welding nanoparticles: from metal colloids to free-standing conductive metallic nanoparticle film

“…Recently, a number of studies have shown that cold-welding [22], lateral self-assembly [23], overgrowth of assembled NP film [24], and self-limited plasmonic welding [25] can effectively fill the interparticle junctions, making highly interconnected NP thin films with improved conductivity. These methods, however, are time-consuming, or need high-temperature annealing, which may cause severe damages to the host substrate, e.g., flexible polyethylene terephthalate (PET) film.…”