Regularities of nitrate electroreduction on Pt(S)[n(100)x(110)] stepped platinum single crystals modified by copper adatoms

Nitrate electroreduction is studied on Pt(S)-[n(100)x(110)] stepped platinum single crystals with 2, 4, and 6 atoms wide terraces modified by copper adatoms. The electrodes were modified by electrodeposition of Cuad in a 0.1 M HClO4 + 0.020 M NaNO3 + 10−5 M Cu(ClO4)2 solution by cycling the potential in the range of 50–350 mV, simultaneously with nitrate reduction. The peak of dissolution of copper adatoms in the nitrate solution is shifted in the positive direction, as compared to the nitrate–free solution, due to the stabilization of copper adatoms by adsorbed NO. This shift is not observed for Pt(210) with the terrace width of only 2 atoms: an increase in the terrace width results in the growing peak shift. The rate of nitrate electroreduction on modified electrodes increases by up to two orders of magnitude and grows at low copper coverages at an increase in the terrace width in the sequence of Pt(210)