Journal of Electroanalytical Chemistry, Vol.743, 93-98, 2015
The use of galvanic displacement in synthesizing Pt-0(Bi)/CNW catalysts highly active in electrooxidation of formic acid
A Pt-0(Bi)/CNW catalyst is synthesized by the galvanic displacement of Bi layers sputtered on carbon nano-walls in a PtCl42- solution (with 0.5 M H2SO4 as the supporting electrolyte). The Pt-0(Bi)/CNW catalysts are characterized by various methods (SEM, XPS, ICP-AES, OCPT, and CVA). It is shown that nearly 90 at.% Bi is displaced. However, no core-shell structure with a sufficiently dense Pt shell is formed. This is explained by the great difference in the type and parameters of Pt and Bi lattices. The Pt-0(Bi)/CNW catalyst exhibits the high stationary specific activity in the formic acid oxidation reaction (FAOR), similar to 30 times exceeding (at 200 mV vs. RHE) the activity of Pt electrodeposits on CNW. The catalytic effect is explained by the inhibition of accumulation of strongly chemisorbed species on the bismuth-modified Pt surface and the formation of new active sites for the one-site adsorption of weakly-bound species through which the direct path of the FAOR passes. Thus, the prospects of the practical application of Pt-Bi catalysts highly active in FAOR are demonstrated. (C) 2015 Elsevier B.V. All rights reserved.