Electrochemical production of hydrogen peroxide (H 2 O 2 ) constitutes a cost-effective and alternative method to the complex and energy-intensive anthraquinone oxidation process. The two-electron water oxidation reaction pathway, while unconventional, is an attractive option for H 2 O 2 generation as it can be combined with suitable reduction reactions to effectuate simultaneous electrosynthesis of valuable chemicals at a large scale. In this work we demonstrate that a carbon-based catalyst, boron-doped diamond (BDD), achieves an H 2 O 2 concentration and production rate of 29.0 mmol dm −3 and 19.7 μmol min −1 cm −2 , respectively, illustrating the capability of BDD as a suitable electrocatalyst for H 2 O 2 formation from water.

The two-electron water oxidation reaction (2e – WOR) is progressively gaining traction as a sustainable approach for in situ electrosynthesis of hydrogen peroxide (H2O2). State-of-the-art 2e – WOR electrocatalysts have shown great promise at low electrical currents yet exhibit diminished electrocatalytic capabilities at larger current densities. Herein, by tailoring the boron doping level of boron-doped diamond (BDD) microfilms, we have fabricated an active, selective, and stable electrocatalyst for the 2e – WOR. Experimentally, we find that our modulated BDD films achieve a peak faradaic efficiency of 87%, as well as a record H2O2 production rate of 76.4 μmol cm–2 min–1, while maintaining a stable electrochemical performance for 10 h at 200 mA cm–2 in carbonate-based solutions. The results reported in this work firmly establish BDD as a primary catalyst candidate for large-scale implementation of the 2e – WOR and synchronously unlock new research avenues for the next-generation design of sp3-structured carbonaceous materials for anodic H2O2 electrosynthesis from water.

No abstract

Disinfection and prevention of re-infection are the decisive treatment steps in endodontic therapy. In this study, boron-doped diamond (BDD) electrodes have been fabricated and used for disinfecting the root canals of extracted human teeth, which had been covered with bacterial biofilms formed by Bacillus subtilis and Staphylococcus epidermidis. The growth of B. subtilis could be successfully impaired, achieving a complete disinfection after 8.5 min treatment time with the success of disinfection depending on the insertion depth of the electrode in the root canal. S. epidermidis could completely be removed after 3.5 min treatment time. A clinically applicable electrode array led to complete disinfection after treatment times of 10 min for S. epidermidis and 25 min for B. subtilis. BDD electrode application allowed for the improved disinfection of root canals and dentin tubules based on a continuous production of reactive oxygen species and their enhanced penetration of dentin tubules most likely due the formation of a continuous stream of small gas bubbles. The treatment times that are required here will be shortened in clinical application, as mechanical shaping of the canal system would precede the disinfection process.

No abstract