Achieving Excellent H Evolution Activity of Silver Nanocatalyst by a Simple Electrochemical Treatment Process.

Silver nanoparticles (AgNPs) were synthesized in an aqueous solution via the reduction of AgNO employing citrate reducing agent. The resultant AgNPs were first assayed for the catalytic H evolution in an acidic electrolyte, namely pH 0.3 HSO solution, showing negligible activity. The AgNPs were then conditioned in the same electrolyte solution while repeating the cyclic potential polarization between -0.25 V and 0.95 V (or 1.8 V) versus RHE. Effects of the electrochemical treatment to the morphology, crystalline, surface chemistry and H evolution catalytic activity of AgNPs were examined. It was found that the electrochemical treatment remarkably boosted the H evolution catalytic activity of AgNPs. The electrochemically activated AgNPs represents an attractive Pt-free catalyst for the H evolution in acidic medium.