Glutaric Acid Rivet Adsorption Induces the Synthesis of Silver Nanosheets for Catalytic Reduction of 4-Nitrophenol to 4-Aminophenol

Although the preparation of silver nanosheets (AgNSs) through diverse methods has largely advanced over the past few decades, the simple and efficient synthesis of high-quality AgNSs under mild conditions remains challenging. Herein, we report a strategy for preparing rounded and sharp-cornered AgNSs with uniform thicknesses of 30-40 nm via simple liquid-phase reduction. Structural characterization revealed that the reduction reaction rate was mediated by coordination of silver ions with the amino groups of gelatins and the carboxylate ions of glutaric acid (GA), effectively suppressing burst nucleation. Density functional theory calculations further identified the adsorption preference of GA anions on Ag(111) as the key factor that dictates the anisotropic growth of silver nanosheets. Furthermore, selective etching with hydrogen peroxide (H₂O₂) mediates the morphological evolution of AgNSs from rounded to sharp-cornered morphologies, effectively removing byproduct particles to achieve sharp-cornered AgNSs in yields exceeding 90%. Catalytic performance testing of the hydrogenation of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) indicates that the mass-normalized rate constants reached 156.67 and 154.22 s^-1 g^-1 for the rounded and sharp-cornered AgNSs, respectively. The conversion rate of 4-NP decreased by only about 2% after five consecutive catalytic cycles. This work provides guidelines for the efficient, economical, and green synthesis of two-dimensional metal nanomaterials while offering valuable insights into the application of the AgNSs in the catalytic reduction of 4-nitrophenol.