Electrochemically Deposited Pd–Pt and Pd–Au Codeposits on Graphite Electrodes for Electrocatalytic H₂O₂ Reduction

Abstract

Improved electrocatalytic activity and selectivity for the reduction of H2O2 were obtained by electrodepositing Pd-Pt and Pd-Au on spectrographic graphite from solutions containing salts of the two metals at varying ratio. The electrocatalytic activity of the resulting binary codeposits for H2O2 reduction was evaluated by means of the redox-competition mode of scanning electrochemical microscopy (SECM) and voltammetric methods. In a potential range from 0 to -600 mV (vs. Ag/AgCl/3 M KCl) at pH 7.0 in 0.1 M phosphate citrate buffer, the electrocatalytic activity of both Pd-Pt and Pd-Au codeposits was substantially improved as compared with the identically deposited single metals suggesting an electrocatalytic synergy of the codeposits. Pd-Pt and Pd-Au codeposits were characterized by X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM). Codepositing with Au caused a change of hedgehog-like shaped Pd nanoparticles into cauliflower-like nanoparticles with the particle size decreasing with increasing Au concentration. Codepositing Pd with Pt caused the formation of oblong structures with the size initially increasing with increasing Pt content. However, the particle size decreases with further increase in Pt concentration. The improved electrocatalytic capability for H2O2 reduction of the Pd-Pt electrodeposits on graphite was further demonstrated by immobilizing glucose oxidase as a basis for the development of an interference-free amperometric glucose biosensor.

Hollow PtPdRh Nanocubes with Enhanced Catalytic Activities for In Vivo Clearance of Radiation‐Induced ROS via Surface‐Mediated Bond Breaking

“…[13] More than two elements not only are the prerequisite to prepare hollow nanostructures through galvanic replacement reactions, but also can force high catalytic activities by the modulation of electronic structures. [18][19][20][21][22] Catalysts have been demonstrated to function as promising antioxidants to scavenge reactive oxygen species (ROS). [23][24][25][26][27][28][29] ROS including superoxide anion radical (O 2 •− ), hydrogen peroxide (H 2 O 2 ), and hydroxyl radical (•OH) are natural byproducts from normal endocellular metabolism, [30] but can be inevitably produced in excessive amount during high-energy radiation therapy such as X-rays, γ-rays, and charged particle irradiation.…”

A novel nonenzymatic biosensor for evaluation of oxidative stress based on nanocomposites of graphene blended with CuI

“…SECM was used to further explore and characterize the electrochemical catalytic activity of relevant sensitive interface of the Gr, CuI, and Gr/CuI, respectively, which was modified on graphite electrode ( Figure S4d) as substrate electrodes [58]. A carbon fiber microelectrode (Ø, 7 ± 2 mm) with glass-to-fiber ratio of 3.0 modified layer of Pt through CV in the range from À0.5 to þ1 V at a scan rate of 50 mV s À1 in 2 mM H 2 PtCl 6 solution with PBS as the supporting electrolyte and the number of CV cycles was ten, which was used as SECM tip.…”

SECM screening of the catalytic activities of AuPd bimetallic patterns fabricated by electrochemical wet-stamping technique

“…For example, it has been applied in detection and quantification of H 2 O 2 [10][11][12][13], which not only is an important species in energy storage field such as intermediate of oxygen reduction reaction [14][15][16][17] but also plays an important role in clinical applications, and environmental analysis. The redox-competition mode (RC) of SECM has been applied for screening of the electrocatalysts in the reduction of H 2 O 2 by Schuhmann and co-workers [18][19][20][21][22]. Moreover, the preparation of electrocatalysts with different defined compositions is still challenging.…”

“…Bard and coworkers [23][24][25][26][27] prepared catalyst spots consisting of mixtures of different metals arranged in high-density arrays on glassy carbon (GC) by reduction of metal salt precursors with sodium borohydride or hydrogen. Schuhmann et al [18,19,28] used a droplet cell to deposit PdPt and PdAu catalyst spots of different compositions on graphite discs. Both of these techniques are not efficient to prepare the alloy patterns and the typical pattern is circle.…”