Stacking faults-rich silver catalysts synthesized via self-assembly for the efficient catalytic reduction of nitrophenols/nitroanilines

Nitrophenols and nitroanilines represent a series of organic pollutants that pose a significant environmental threat. Nevertheless, their catalytic reduction products — aminophenols and phenylenediamine — are regarded as valuable industrial intermediates. Therefore, identifying a highly active and cost-effective catalyst is essential for achieving the efficient catalytic conversion of nitrophenol and nitroaniline. Here, we employed a liquid-phase reduction approach to synthesize silver catalysts with varied morphologies and abundant defects (stacking faults and microporosity) through a rapid self-assembly process induced by gelatin. We found that the conformation of small polypeptide chains in gelatin can be regulated via controlled temperature gradients during synthesis, thereby directing the self-assembly of silver nanostructures into 2D nanosheets and 3D spherical nanoflowers. Spherical aberration transmission electron microscopy revealed the presence of abundant stacking faults on the surface of the silver catalyst. Therefore, the silver catalysts exhibited excellent catalytic activity for the catalytic reduction of 4-nitrophenol (4-NP), 2-nitrophenol (2-NP), and p-nitroaniline (p-NA), with reaction rate constants of 1.20 × 10 −2  s −1 , 1.04 × 10 −2  s −1 , and 1.23 × 10 −2  s −1 , respectively. Furthermore, a detection limit of 50 nM for 4-NP was achieved using AgNSs-modified glassy carbon electrodes.