NADPH-guided synthesis of iodide-responsive nanozyme: synergistic effects in nanocluster growth and peroxidase-like activity

Reduced coenzyme II acts as both reducing and capping agents in the growth of AgPd nanoclusters within a suitable range of [K2Pd(NO2)4]/[AgNO3]. A remarkable acceleration occurs in the growth kinetics of AgPd nanoclusters with respect to monometallic Pd or Ag. AgPd nanoclusters display a marked electron donation from Ag to Pd, thereby contributing to the enhancement of metallic Pd0 atoms. The AgPd nanoclusters exhibit better peroxidase mimicking activities relative to their monometallic counterparts. Addition of iodide ions significantly inhibits the peroxidase mimicking activity of Ag1Pd1 nanozyme. Hence, the Ag1Pd1-catalyzed oxidation of 3,3′,5,5′-tetramethylbenzidine by H2O2 is greatly suppressed. The peroxidase-like activity of Ag1Pd1 nanozyme exhibits a sensitive response to iodide ions in the range of 0.5 ~ 180 nM. AgPd nanozyme possesses a desirable selectivity toward iodide ions with respect to sulfide ions. This work would provide guidance for developing biomimetic nanomaterials in the areas of biosensing, separation, nanotechnology and green synthesis.