A low-temperature dealloying technique was developed to tailor the characteristic length scale of nanoporous gold for advanced functional applications. By systematically investigating the kinetics of nanopore formation during free corrosion, the authors experimentally demonstrated that the dealloying process is controlled by the diffusion of gold atoms at alloy/electrolyte interfaces, which strongly relies on the reaction temperatures. Low dealloying temperatures significantly reduce the interfacial diffusivity of gold atoms and result in an ultrafine nanoporous structure that has been proved to be useful with improved chemical and physical properties.
We report transmission electron tomography of nanoporous gold fabricated by chemically dealloying Au35Ag65 films. A number of algorithms were employed to quantitatively characterize the complex three-dimensional nanoporous structure. It was found that gold ligaments and nanopore channels are topologically and morphologically equivalent, i.e., they are inverses of each other in three-dimensional space. Statistical analysis reveals that this bicontinuous nanostructured material is actually quasiperiodic and has, on average, a near zero surface curvature. These quantitative measurements will help in understanding the structural stability of nanoporous gold and in modeling its physical and chemical performances.
In
the environment, microplastics are subjected to multiple aging
processes; however, information regarding the impact of aging on the
environmental behavior of microplastics is still lacking. This study
investigated the alteration properties of polystyrene and high-density
polyethylene microplastics by heat-activated K2S2O8 and Fenton treatments to improve the understanding
of their long-term natural aging in aquatic environments. Our results
indicated that the O/C ratio was an alternative parameter to the carbonyl
index (CI) to quantitatively describe the surface alteration properties
of microplastics. The correlation model of the O/C ratio or CI versus
alteration time was developed and compared by natural alteration of
microplastics in freshwater samples. Moreover, the regression equation
of the equilibrium adsorption capacity of altered microplastics versus
the O/C ratio and average size was proposed. This study is the first
effort in differentiating the relationships between the alteration
properties and alteration time/adsorption capacity of microplastics,
which would be helpful for predicting the weathering degree and accumulation
of hydrophilic antibiotics onto aged microplastics in aquatic environments.
This research develops promising strategies to accelerate the aging
reactions using advanced oxidation processes, which would provide
further information to assess the microplastic pollution in actual
environments.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.