Photoelectrochemical Production of Hydrogen Peroxide with TiO₂ and 1,5-Di(thien-2-yl)-9,10-anthraquinone via a Selective Two-Electron Oxygen Reduction Reaction in the Two-Compartment Cell

Abstract

The industrial process of hydrogen peroxide (H 2 O 2 ) synthesis proceeds through the hydrogenation of anthraquinone followed by successive oxidation in an organic solvent. This process is a multistep synthesis that is far away from green synthesis. An alternative photoelectrochemical (PEC) H 2 O 2 production method requires only sunlight and water. Herein, we established the direct production of H 2 O 2 by using a twocompartment PEC cell composed of TiO 2 nanorods hydrothermally grown on fluorine-doped tin oxide as a photoanode for water oxidation and 1,5-di(thien-2-yl)-9,10-anthraquinone (AQTh) anchored carbon cloth as a cathode for the selective two-electron (2e − ) reduction of oxygen. This photoanode and cathode are positioned in an anodic compartment and a cathodic compartment of a two-compartment cell, respectively. The Nafion membrane (N-117) separates these two compartments. This PEC cell continuously produces H 2 O 2 at −0.1 V RHE applied voltage, which reaches 60 μM after 3 h. The density functional theory study is carried out to better understand the H 2 O 2 production mechanism and the role of thiophene substituents on anthraquinone.

A TiO2 nanorod and perylene diimide based inorganic/organic nanoheterostructure photoanode for photoelectrochemical urea oxidation

“…3c and S8a†) consists of two doublet peaks centered at 459 eV and 464.73 eV representing the Ti 2p 1/2 and Ti 2p 3/2 states of Ti 4+ . 51 The XPS of Ti 2p for both TiO 2 and TiO 2 /PDIEH reveals the same type of Ti cluster in both materials. The O 1s spectrum (Fig.…”

“…The PEC water oxidation onset potential is the potential in the LSV plot recorded in KOH solution at which the slope of J ph meets the dark current. 51 The water oxidation onset potentials shown by the TiO 2 NR and TiO 2 /PDIEH NH photoanodes are 0.20 V RHE and 0.30 V RHE , respectively (Fig. 4a) and exhibit anodic shifts of 0.1 V in the onset potential of the TiO 2 /PDIEH NH photoanode compared to the TiO 2 NRs.…”

Introducing Platinum Nanoparticles on Inorganic/Organic Nanoheterostructures for Enhancing their Efficiency toward the Photoelectrochemical Urea Oxidation Reaction

“…The XPS spectrum of Ti 2p contains two major peaks at 459.07 and 464.73 eV representing the Ti 2p 3/2 and Ti 2p 1/2 states of Ti­(IV), respectively (Figure (a)). The other peaks at 458.17 and 463 eV correspond to the Ti 2p 3/2 and 2p 1/2 states associated with Ti 3+ , respectively. , The XPS spectrum of O 1s consists of two intense peaks at 530.11 and 532.21 eV corresponding to lattice oxygen (O L ) and the V O in the TiO 2 matrix, respectively (Figure (b)). , The presence of a small peak at 533.24 eV corresponds to the CO group from NDIPh . The XPS spectrum of N 1s contains two peaks positioned at 400.51 and 402.96 eV assigned to the imide ((OC)-N-(CO)) functional group and the X-ray oxidized charged nitrogen bipolariton, respectively (Figure (c)) .…”