Pt-Cu electrocatalysts for methanol oxidation prepared by partial galvanic replacement of Cu/carbon powder precursors

Effects of the Electrodeposition Time in the Synthesis of Carbon-Supported Pt(Cu) and Pt-Ru(Cu) Core-Shell Electrocatalysts for Polymer Electrolye Fuel Cells

“…Note that the linear sweep voltammograms in Figure 9 have been obtained at 20 mV s −1 and 1.0 M CH3OH. The mass activity reported for methanol oxidation at the same potential for Pt-Cu core-shell alloy with 9.5 wt % Pt at 5 mV s −1 in 0.5 M CH3OH + 1 M HClO4 was about 140 mA mgPt −1 [28]. Therefore, the results reported in curve a of Figure 9 can be considered good.…”

“…In the case of formic acid oxidation, the mass activity also at 0.7 V for highly dispersed Pt-Cu/C catalysts via surface substitution and etching separation at 50 mV s −1 in 0.25 M HCOOH + 0.5 M H2SO4 was about 250 mA mgPt −1 [30]. In a different synthesis process, novel excavated rhombic dodecahedral PtCu3 [28]. Therefore, the results reported in curve a of Figure 9 can be considered good.…”

“…The most part of the Pt-Cu/C catalysts in which the galvanic exchange has been used, have been prepared starting from Cu/C precursors obtained by chemical reduction of Cu 2+ [24,[26][27][28]30]. They have been mainly applied to methanol [24,28], ethanol [27] and formic acid oxidation [25,30] and oxygen reduction [26] The synthesis of nanoparticle catalysts starting from the electrochemical reduction of Cu 2+ is scarcely found in the literature [18]. There is also an additional interest in studying whether there is a further positive effect in the introduction of Ru deposited species.…”

In situ liquid-cell electron microscopy of silver–palladium galvanic replacement reactions on silver nanoparticles

“…Such hollow and porous structures have drawn interest as they can shift plasmon resonances compared with those of solid nanoparticles 5,10 , may provide nanoscale containers for biomedical applications such as diagnostics and drug delivery 11 , are of use as contrast enhancement agents in optical imaging such as optical coherence 12 , photoacoustic tomography 13,14 , and are found to be highly active in catalysis [15][16][17][18][19][20] and electrocatalysis 21,22 . The galvanic replacement reaction is critical in the advanced two-step synthesis of fuel cell electrocatalysts with reduced precious metal loadings, limited to a thin surface layer or even a monolayer on top of less expensive metal nanoparticles [23][24][25][26][27][28][29][30][31][32][33] . The electrocatalysts obtained either via the transmetalation of an underpotentially deposited 23,26,28 or electrodeposited 27,[29][30][31][32][33] monolayer or thin layer of a less precious metal by a precious metal upon immersion into a complex solution of Pt, Pd or Au ions 23,[26][27][28][29][30][31][32]…”

“…The galvanic replacement reaction is critical in the advanced two-step synthesis of fuel cell electrocatalysts with reduced precious metal loadings, limited to a thin surface layer or even a monolayer on top of less expensive metal nanoparticles [23][24][25][26][27][28][29][30][31][32][33] . The electrocatalysts obtained either via the transmetalation of an underpotentially deposited 23,26,28 or electrodeposited 27,[29][30][31][32][33] monolayer or thin layer of a less precious metal by a precious metal upon immersion into a complex solution of Pt, Pd or Au ions 23,[26][27][28][29][30][31][32][33] , or by partial galvanic replacement 24,25 exhibit enhanced activity compared to the most active Pt catalysts [23][24][25][26][27][28][29][30][31][32][33] .…”