980 nm NIR light driven overall water splitting over a combined CdS–RGO–NaYF4–Yb3+/Er3+ photocatalyst

Abstract

Infrared light (NIR) accounts for more than 50% of the energy donated by the Sun to the Earth, but most of this type of energy is not utilized in photocatalytic reactions. The up-conversion of infrared light into visible light is a probable strategy to utilize NIR in solar energy storage and conversion into hydrogen. Herein, a cooperative photocatalyst consisting of RGO, CdS and an up-conversion component (NaYF₄–Yb³⁺/Er³⁺) has been identified as an excellent photocatalyst for overall water splitting to hydrogen. By uniting an up-conversion component with a visible light catalyst, a cooperative catalyst has been developed and 980 nm NIR driven water splitting has been achieved. RGO and CN were selected, and their water splitting performances based on their incorporation into combined catalysts were compared. The results indicated that only RGO had a significant promotion effect on photocatalytic water splitting activity due to its good conductivity on its huge net-like 2D structure. A highest hydrogen evolution rate of 4.54 μmol g⁻¹ h⁻¹ was achieved.