dc.description.abstract | In this study, cyclic voltammetry (CV) and scanning tunneling microsope (STM) were used to investigate the structure of lead modification on the surface of the Pt (100) electrode and its catalytic effect on formic acid oxidation. In the experiment, the Pt(100) electrode was annealed with a hydrogen flame and cooled under hydrogenblowing, and the lead was modified on the Pt(100) electrode by immersion method or addition method, and the structure of √2×√2 was shown under STM imaging at -0.2 V(vs. Ag/ AgCl). When the potential was shifted to -0.1 V, the lead overlayer structure results was transformed into√2×√2. The coverage of lead on the electrode surface was 0.5 by cyclic voltammetry for lead oxidation and exfoliation. In addition, when the scanning range of cyclic voltammetry is extended to the overpotential of lead, the deposition of multilayer lead will first expand outward from the two dimensional direction, and then slowly grow into a large flat island in the dimensional direction, and at the same time, the platinum surface and the underlying lead will be mixed to form an alloy under the influence of the potential, so that when the potential is moved to 0 V, the single layer lead√2×√2structure and the platinum surface 1×1 structure will be transformed into disordered and rough surface
The Pt(100) electrode after lead premodification can effectively inhibit the adsorption of carbon monoxide, an intermediate in the formic acid oxidation reaction, so that once the bare Pt(100) is adsorbed by carbon monoxide after formic acid oxidation, it must have formic acid oxidation activity after the potential is 0.5 V, and the formic acid oxidation phenomenon begin to occur when it reaches -0.1 V in advance, and the current is also increased from 0.41 mA/cm2 to 7.1 mA/cm2. The results showed that the Pb-modified Pt(100) electrode also had a catalytic effect on formaldehyde, the oxidation potential was 0.1 V earlier than that of bare Pt(100) and the maximum
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oxidation current was increased from the 1.1 mA/cm2 to 4.1 mA/cm2,but it did not have an obvious catalytic effect on methanol oxidation, which breaks the carbon-hydrogen bond to form a carbon dioxide intermediate, but the carbon-oxygen double bond in the methanol molecule is adjacent to carbon instead of hydrogen, so the overall catalytic effect is not well. | en_US |