Photoelectrochemical Degradation of Organic Pollutants Coupled with Molecular Hydrogen Generation Using Bi₂O₃/TiO₂ Nanoparticle Arrays

Abstract

The growing world population is closely associated with the increased demand of safe drinking water and sustainable energy production. This drives the focus of the scientific community to work toward water remediation and clean energy generation. The combination of photoelectrooxidation of pollutants at the anode with simultaneous hydrogen gas production at the cathode is a smart strategy to address these problems. Herein, we have designed a bifunctional photoelectrocatalytic system consisting of a self-standing photoanode to degrade the water pollutant molecules with simultaneous production of molecular hydrogen at the cathode. The photoanode was prepared by coating Bi2O3 over the surface of self-standing TiO2 nanorods. Thus, prepared photoelectrodes show high degradation efficiency for rhodamine molecules, where direct oxidation of rhodamine by the holes generated under solar light illumination was detrimental for its activity. During simultaneous pollutant removal and energy production experiments, the anode shows 100% degradation of pollutant molecules while the cathode shows high hydrogen gas production (128 mM cm–2 h–1). The prepared composite showed higher efficiency of visible-light absorbance, high charge generation capability, and low charge transfer resistance at the interface as determined via several characterizations, compared to the bare titania. The catalyst is easy to prepare and robust in activity for several kinds of pollutant molecules tested. Its robust activity, high stability, and durability open up an avenue for the wastewater treatment with simultaneous renewable energy production technologies.

Pd/Au bimetallic nanoparticle-anchored BiVO4/TiO2 nanotube arrays toward efficient photoelectrocatalytic Suzuki–Miyaura reactions

“…Combining the above-mentioned experimental results with previous literature reports, 22,[45][46][47] a possible mechanism for the photoelectrocatalytic Suzuki cross-coupling reactions was proposed using bromobenzene and phenylboronic acid as a model reaction (Fig. 4).…”

Effect of bismuth doping on the crystal structure and photocatalytic activity of titanium oxide

“…6b, the Ti 2 p high-resolution spectrum of Bi 2 O 3 -doped TiO 2 nanoparticles revealed two distinct peaks at 458.57 and 464.3 eV, assigned to the Ti 2p 3/2 and Ti 2p 1/2 orbitals of Ti 4+ (TiO 2 ), respectively. 33,34 Moreover, the peak separation of 5.7 eV between these two Ti 2p doublets indicated the existence of Ti 4+ ions in the TiO 2 lattice. 35–38 Besides the peaks of Ti 4+ ions, less intense peaks were also observed corresponding to a small content of Ti 2+ and Ti 3+ ions.…”

“…The split of 5.3 eV between the Bi 4f doublets conrmed the Bi 3+ valence state and Bi 2 O 3 structure in the prepared catalyst. 34 For comparison, the XPS analyses of pure a-Bi 2 O 3 mentioned in previous studies 33,40,42 were used. The binding energy of the Bi 4f 7/2 and Bi 4f 5/2 peaks of pure a-Bi 2 O 3 were 158.6 and 163.9 eV, respectively.…”

Push–Pull Engine─Electron Pumping by Anchored Ligands over ZnO/C: Boosting Photo-Fenton-Like Catalysis without Additional Oxidants

“…Notably, the porous carbon matrix as in ZnO/C HNMs often exhibits active sites that can reduce O 2 to H 2 O 2 . ,, To examine the role of various reactive species in pollutant degradation, a series of quenching experiments were conducted. t-Butyl alcohol (TBA), p-benzoquinone (pBQ), l -histidine ( l -His), and Na-azide were used, respectively, as chemical scavengers for OH·, HO 2 · /O 2 –. , H 2 O 2 /OH·, and 1 O 2 .…”

“…34,56,57 To examine the role of various reactive species in pollutant degradation, a series of quenching experiments were conducted. t-Butyl alcohol (TBA), 58 p-benzoquinone (pBQ), 59 L-histidine (L-His), and Na-azide were used, respectively, as chemical scavengers for OH•, HO 2…”