Comparative study of oxidation ability between boron-doped diamond (BDD) and lead oxide (PbO2) electrodes

Abstract

The electrochemical oxidation capabilities of two high-performance electrodes, the boron-doped diamond film on Ti (Ti/BDD) and the lead oxide film on Ti (Ti/PbO 2 ), were discussed. Hydroxyl radicals (·HO) generated on the electrode surface were detected by using p-nitrosodimethylaniline (RNO) as the trapping reagent. Electrochemical oxidation measurements, including the chemical oxygen demand (COD) removal and the current efficiency (CE), were carried out via the degradation of p-nitrophenol (PNP) under the galvanostatic condition. The results indicate that an indirect reaction, which is attributed to free hydroxyl radicals with high activation, conducts on the Ti/BDD electrode, while the absorbed hydroxyl radicals generated at the Ti/PbO 2 surface results in low degradation efficiency. Due to quick mineralization which combusts PNP to CO 2 and H 2 O absolutely by the active hydroxyl radical directly, the CE obtained on the Ti/BDD electrode is much higher than that on the Ti/PbO 2 electrode, notwithstanding the number of hydroxyl radicals produced on PbO 2 is higher than that on the BDD surface.

Gd‐Ni‐Sb‐SnO2 electrocatalysts for active and selective ozone production

“…Among these, β-PbO 2 is known to have relatively high selectivity for EOP but its toxicity is generally regarded as infeasible for water treatment applications. [4][5][6][7][8][9][10] Subsequently, the focus of the literature has transitioned to investigating alternative materials such as doped SnO 2 . Wang et al first reported an ozone current efficiency of approximately 30% utilizing nickel and antimony doped tin oxide (Ni-Sb-SnO 2 ) on titanium substrates.…”

“…Given the thermodynamic challenges of direct oxidation, catalytically active materials with a high selectivity for ozone have been a topic of ongoing research. Among these, β‐PbO 2 is known to have relatively high selectivity for EOP but its toxicity is generally regarded as infeasible for water treatment applications 4–10 . Subsequently, the focus of the literature has transitioned to investigating alternative materials such as doped SnO 2 .…”

Step-by-step guide for electrochemical generation of highly oxidizing reactive species on BDD for beginners

“…Typically, the limiting current can be found in electrooxidation systems as a function of time in the chemical oxygen demand (COD) (Eq. 2 ) ( Wei J. J. et al, 2011 ; Ochoa-Chavez et al, 2018 ). where i lim is the limiting current, F is Faraday’s constant, and k m is the mass transfer coefficient.…”

The Mechanism of Oxidation of Formic Acid in Acidic Solutions on Boron‐Doped Diamond Electrodes: A Quantum Chemical Study

“…[1-6and refs therein] In the case of electrochemical combustion of organic compounds two mechanisms of oxidation are discussed in the literature: a) a direct transfer of an electron from the molecule to the electrode, b) formation of a reactive HO radical by oxidation of water at an electrode, which then reacts with the organic molecule in solution. [1][2][3][4][5][6][7][8][9][10][11][12] The former is possible if the reactant can adsorb on the electrode surface, for example on Au or Pt, while the second mechanism is expected to prevail at special inert electrodes with low adsorption properties. A typical example of the latter is the boron-doped diamond (BDD) electrode, on which the hydroxyl radical generation and incineration of carboxylic acids can proceed via an outer sphere mechanism, without adsorption of intermediates.…”