Modified, Solvothermally Derived Cr-doped SnO₂Nanostructures for Enhanced Photocatalytic and Electrochemical Water-Splitting Applications

Cr-doped SnO₂nanostructures with a dopant concentration ranging from 1 to 5% have been successfully prepared using low-temperature modified solvothermal synthesis. The as-prepared nanoparticles showed a rutile tetragonal structure with a rough undefined morphology having no other elemental impurities. The particle shape and size, band gap, and specific surface area of the samples were investigated by scanning electron microscopy, transmission electron microscopy (TEM), high-resolution TEM, UV-visible diffused reflectance spectroscopy, and Brunauer-Emmett-Teller surface area studies. The optical band gap was found in the range of 3.23-3.67 eV and the specific surface area was in the range of 108-225 m²/g, which contributes to the significantly enhanced photocatalytic and electrochemical performance. Photocatalytic H₂generation of as-prepared Cr-doped SnO₂nanostructures showed improved effect of the increasing dopant concentration with narrowing of the band gap. Electrochemical water-splitting studies also stressed upon the superiority of Cr-doped SnO₂nanostructures over pristine SnO₂toward hydrogen evolution reaction and oxygen evolution reaction responses.