Effect of cadmium and lead adatoms on the reduction kinetics of peroxodisulfate anions at platinized platinum in acid solutions

Abstract

The reduction of peroxodisulfate anions on a rotating Pt/Pt disk electrode in solutions of sulfuric and perchloric acids with or without cadmium and lead salts is studied. At E r > 0.2 V (RHE) the reduction rate in HClO 4 exceeds that in H 2 SO 4 , but at E r < 0.2 V, the process in HClO 4 is strongly inhibited upon approaching E r = 0. Lead adatoms catalyze the process, while cadmium adatoms inhibit it in H 2 SO 4 and accelerate it at E r < 0.2 V in HClO 4 . The results are interpreted by taking account of the specific adsorption of sulfuric-acid anions and their co-adsorption with cadmium cations, as well as the adsorption of peroxodisulfate anions on the Pt surface modified by lead and cadmium ions in perchlorate solutions.

Review—Electroreduction of Peroxodisulfate: A Review of a Complicated Reaction

“…Unfortunately, they did not compare the currents acquired using the platinized Pt electrodes with the theoretical currents. Similar electrochemical responses are shown by Nikiforova and Petrii 70 in Figure 2 in their published work. Furthermore, the peaks attributed to the surface processes for Pt electrodes such as hydrogen adsorption and desorption as well as oxide formation and removal are enhanced due to higher amount of adsorption sites.…”

“…This means that metal adspecies can be deposited on electrode surfaces even without applying an overpotential, and remain adsorbed even after rinsing the electrode and transferring it into a solution in the absence of the metal cations of interest. 53 Several metal adspecies such as lead, 56,70 cadmium (Cd), 70 thallium, 56 and bismuth 53,56 have been used to study the effects of adsorbed species on the reduction of persulfate. All of the groups have employed rotating disk electrodes for their work.…”

“…Other electrode materials.-The electroreduction of peroxodisulfate has also been investigated using other electrode materials: leadand thallium-adsorbed silver (Ag), 79 Cd-adsorbed platinized Pt, 70 riboflavin/graphene quantum dots-modified glassy carbon, 80 ruthenium oxide/thionine-and ruthenium oxide/celestine blue-modified glassy carbon, 81 mercury, [82][83][84] Cd, [85][86][87] bismuth, 86 Prussian blue, 88 and BDD. 89 However, none of these materials exhibit diffusion-controlled currents.…”

Peroxodisulphate reduction as a novel probe for the study of platinum single crystal/solution interphases

“…Strong increase of Pt activity towards PS reduction by Pb, Tl and Bi upd adlayers was also presented [23,24], the effect of Bi being the strongest in acidic media. Catalysis by Pb adatoms was confirmed later for slightly platinized platinum [25]. In this paper, Cd effect was found to be more complex as compared to Pb effect.…”

Peroxodisulfate reduction on platinum stepped surfaces vicinal to the (110) and (100) poles

“…In particular, the variation of the potential in the diffuse part of the double layer leads to what has been called the Frumkin effect [42]. For this reason, PDS reduction has been extensively investigated in a broad range of cathode materials [38,40,41,[43][44][45][46]. This reaction is often described as taking place through several parallel pathways that can be grouped in two extreme situations [42,46].…”