Fast surface dynamic processes of thiocyanate adsorbed on a nanostructured Pt microelectrode were studied by in situ step-scan time-resolved microscope FTIR spectroscopy(in situ SSTR-MFTIRS) at a time resolution of 100 s.It was found that SCN adsorbs preferentially on Pt surface through N atom at low potential,while through S atom at high potential.The potential-induced orientation conversion between N-and S-bounded forms is very reversible,and occurs only within 2 ms after potential alternation.However,the rate constant(4*103s-1) of conversion from N-to S-bounded adsorption is nearly double to that of the reverse process(2*103s-1).The difference in kinetics of two processes may be explained through the hard-soft acid-base principle.
