Visible and near-infrared driven Yb3+/Tm3+ co-doped InVO4 nanosheets for highly efficient photocatalytic applications

Abstract

To effectively enhance the utilization of clean sunlight energy, harvesting a large percentage of near infrared (NIR) light is significant. One of the commonly used effective methods for modifying semiconductors is by co-doping upconversion materials on semiconductors to heighten the photocatalytic efficiency. In this work, Yb³⁺/Tm³⁺ co-doped InVO₄ nanosheets were synthesized by a facile hydrothermal path, and the crystal phases, morphologies, surface chemical compositions, as well as optical properties were characterized. Yb³⁺/Tm³⁺ co-doped InVO₄ revealed significantly enhanced photoactivity towards chromium(VI) reduction and methyl orange oxidation under visible or NIR light irradiation. Furthermore, 5YT-IV presented the highest electrocatalytic performance and photocatalytic production of H₂O₂ under visible light irradiation, requiring low overpotential and low Tafel slope (390 mV dec⁻¹) for hydrogen evolution reaction than that of the bare InVO₄ (731 mV dec⁻¹), and as well improved the yield of photocatalytic H₂O₂ production by about 3.5 times. This was primarily ascribed to intensive light absorption resulting from the benign upconversion energy transfer of Yb³⁺/Tm³⁺ and the boosted charge separation caused by the intermediate energy states. Moreover, the presence of h⁺ and ˙O₂⁻ as the main oxidative species played a significant role during the photocatalytic oxidation process of methyl orange and electrons played a decisive role in Cr(VI) reduction. This study provides a promising platform for efficiently utilizing the visible-NIR energy of sunlight in the field of photocatalytic H₂O₂ production and for alleviating environmental pollution in future.