Electrocatalytic reduction of hydrogen peroxide on a palladium‐modified carbon paste electrode

Abstract

A palladium-dispersed carbon paste electrode was used for the electrocatalytic reduction of hydrogen peroxide. After cycling the potential between 0.4 and -0.8V (vs. SCE) in pure dilute alkaline solution M NaOH), the resulting electrode surface exhibited stable and sensitive electrocatalytic response foir hydrogen peroxide. The involved catalytic mechanism was thoroughly investigated. The electrocatalytic effect was attributed to electrogenerated elemental palladium at the electrode surface. The catalytic reduction of hydrogen peroxide proceeds via the hydroxyl radical, OH * . Dissolved oxygen can also be catalytically reduced in a similar way to hydrogen peroxide.The height of the cathodic catalytic current peak, as obtained by linear sweep voltammetry (LSV) was directly proportional to the hydrogen peroxide concentration over a very wide concentration range (0.1-600mgL-'). The detection limit (30) was calculated as 5OpgL-I HzOZ.

Generation of OH radicals at palladium oxide nanoparticle modified electrodes, and scavenging by fluorescent probes and antioxidants

“…Electrodes made with 15 deposition cycles during the film electrodeposition step were used for the rest of the work. The current enhancement for the reduction of PdO in the presence of H 2 O 2 or dissolved oxygen has been reported previously [8,12,14], and interpreted as a catalytic mechanism where reactive oxygen species (e.g. OH radical) generated from the oxygen reduction and the dissociation of H 2 O 2 can re-oxidise the reduced palladium metal exposed, thereby recycling the palladium oxide at the nanoparticle surface.…”

“…The oxygen reduction is electrocatalysed by Pd in alkaline solutions [5]. H 2 O 2 is either further reduced to H 2 O or dissociates to OH radical on palladium or platinum and platinum alloy clusters and surfaces [8,22].…”

“…Palladium and other platinum-group metal islands at the nanometer to micrometer range have been produced on different substrates and used as catalysts for oxygen reduction reaction, which is one of the most extensively investigated processes in electrochemistry mainly for fuel cell research [4][5][6]. Palladium nanoparticles have also been used in electroanalysis as electrocatalyst in modified electrodes for the detection of H 2 O 2 , O 2 , NO, glucose and hydrazines [7][8][9][10][11][12][13][14].…”

Carbon Paste Electrodes in Facts, Numbers, and Notes: A Review on the Occasion of the 50‐Years Jubilee of Carbon Paste in Electrochemistry and Electroanalysis

“…For both CMCPEs and CP-biosensors, numerous materials of such a origin were used, comprising: i) plants and plant tissues (e.g., alga [131], lichen [132], moss [133], tobacco [134], pea seedlings [135], or grass weed [136]); ii) fruits and vegetables (often as natural sources of enzymes); e.g., banana [137]; orange slice [138], apple [139], pear and peach [140], avocado [141], annona pear [142], pineapple [143], or potatoes [140]; iii) mushrooms [140,144,145], iv) bacteria and viruses [146,147]); v) natural macromolecules (e.g., chitin [148], chitosan [149], or keratin [150]); vi) other materials such as liquid crystals [151,152], metal dispersions [153,154], or pumice (sea foam [155]). …”

Carbon Paste Electrodes

“…Metals: They can be used to mimic corresponding metal electrodes; they can be employed as metallic micro-or nanoparticles or as thin films in the form of metallized carbon [127][128][129]. The main goal is to exploit some specific characteristics of the element, for example, the catalytic activity of platinum for the determination of hydrogen peroxide [127].…”