Ultrathin Au–Ag Heterojunctions on Nanoarchitectonics Based Biomimetic Substrates for Dip Catalysis

Nanoarchitectonics has gained recent attention from researchers and can be utilized in the development of catalytic systems with unique morphological features, high surface area and engineered catalytic sites. In this work, biomimetic substrates have been fabricated by replicating wings of a grasshopper insect with interesting surface hierarchical architecture by employing a soft lithography technique. Further, the substrates were engineered to form a hetero-nanojunction of gold and silver nanolayers by using the sputtering technique. The replicated substrates possess multi-wall supported sharp edged pods type morphology and provide a good degree of adhesion to the deposited metal layers with increased surface area in comparison to a flat control substrate. The catalytic potential of these metal-coated nanoarchitectonics-based substrates was examined as dip catalysts for degradation of a model organic pollutant, methylene blue in the presence of sodium borohydride as a reducing agent. The biomimetic substrate showed higher photocatalytic degradation of methylene blue due to the enhanced plasmonic effect in comparison to the flat control substrate. The mechanism of the degradation has been discussed in detail in the presence and absence of light irradiation. This work paves way for the design and development of recyclable and efficient dip catalysis substrates by combining the nanoarchitectonics and biomimetic approaches.