Specific and mass activity of silver nanocube and nanoparticle-based catalysts for electroless copper deposition

Catalytic activity normalised with respect to mass and electrochemical surface areas (ESA) are used herein to estimate the mass activity and specific activity, respectively, of Ag nanomaterials for catalysing electroless copper deposition (ECD). The activities and resulting average deposition rates were compared for Ag nanocubes enclosed by (1 0 0) planes and Ag nanoparticles. On the basis of mass evaluation and deposition kinetics measured using a quartz crystal microbalance (QCM), the mean mass activities of nanocubes and nanoparticles are determined to be 1.228 and 1.923, respectively. The Ag nanocubes show weaker mass activity and smaller ESA than do Ag nanoparticles. The resulting average deposition rates in terms of mass activity are 3.5 x 10−3 s−1 and 5.5 x 10−3 s−1 for nanocubes and nanoparticles, respectively. In contrast, a careful comparison of specific activity demonstrates that the Ag nanocubes show a better activity (5.4 x 10−2 mg cm−2) than do Ag nanoparticles (4 x 10−2 mg cm−2). The average deposition rates in terms of specific activity are 1.54 x 10−4 mg cm−2 s−1 and 1.16 x 10−4 mg cm−2 s−1 for nanocubes and nanoparticles, respectively; thus, nanocubes enable faster ECD. Similarly, in the Tafel plot normalised to the ESA, the specific current density corresponding to nanocubes were found to be higher than that in the case of nanoparticles for formaldehyde oxidation. The QCM and Tafel results demonstrate that the (1 0 0) planes in Ag nanocubes can enhance the catalytic activity of the nanocubes in ECD.