P–N Heterojunction System Eu‐Doped ZnO@GO for Photocatalytic Water Splitting

• Published in: Global challenges 2023-04, Vol.7 (4), p.2200106-n/a
• Main Authors: Gurbani, Neeta, Chouhan, Neelu
• Format: Article
• Language: English
• Subjects: Catalytic activity; Cetyltrimethylammonium bromide; Charge transfer; Electrochemistry; Electrodes; europium‐doping; Glass substrates; Graphene; graphene oxide; Heterojunctions; Hydrogen; hydrogen generation; Hydrogen production; Light; Light sources; Microscopy; Morphology; N-type semiconductors; Nanocomposites; P-n junctions; P-type semiconductors; Particle size; Photocatalysis; Recombination; Spectrum analysis; Splitting; Water splitting; Zinc oxide; ZnO
• ISSN: 2056-6646; 2056-6646
• DOI: 10.1002/gch2.202200106

Here, a feather‐like Eu‐doped ZnO (particle size ≈ 34.87 µm and Eg ≈ 3.13 eV) nanoassembly is synthesized by using the capping agent cetyltrimethylammonium bromide‐supported hydrothermal method. The Eu‐doped ZnO is loaded onto the graphene oxide (GO) surface as Eu‐doped ZnO@GO (particle size ≈ 23.07 µm and Eg ≈ 0.79 eV) and applied to measure the photocatalytic water splitting activity in 20% CH3OH under a 300 W Xe light source. Eu‐doped ZnO@GO exhibits the higher hydrogen generation activity of 255.8 µmol h−1 g−1 that is 159 and 1.5 times more than the pristine GO and Eu‐doped ZnO systems, respectively. Eu‐doped ZnO enhances the photocatalytic activity of GO because the p–n junction formed between GO and Eu‐doped ZnO might support the charge‐transfer and suppress charge recombination. The light harvesting power of Eu‐doped ZnO@GO makes the charge transfer smooth through the GO network. Surface photovoltage and electrochemical impedance studies of the Eu‐doped ZnO@GO composite, reveal that GO acts as the p‐type semiconductor and Eu‐doped ZnO works as an n‐type semiconductor and their interface facilitates the p–n junction to ease charge separation and results in enhanced the water‐splitting efficiency. Eu‐doped ZnO@GO (graphene oxide) with p–n junction is fabricated by a hydrothermal method and used for photocatalytic water splitting. The Eu‐doped ZnO@GO composite exhibits 159 and 1.5 times higher rate of hydrogen generation than the pristine GO and Eu‐doped ZnO systems, respectively. Here, GO acts as the p‐type and Eu‐doped ZnO worked as an n‐type semiconductor to suppress the charge‐carrier's recombination.