Highly efficient near-infrared light photocatalytic hydrogen evolution over MoS2 supported Ta2O5 combined with an up-conversion luminescence agent (beta-Tm3+,Yb3+:NaYF4/MoS2-Ta2O5 nanocomposite)

Here, an effective infrared-ultraviolet up-conversion luminescence agent (beta-Tm3+, Yb3+: NaYF4) is synthesized by a hydrothermal method and the corresponding photocatalyst (beta-Tm3+, Yb3+: NaYF4/MoS2-Ta2O5) is successfully prepared. The compositions and morphologies of the prepared beta-Tm3+, Yb3+: NaYF4, MoS2-Ta2O5 and beta-Tm3+, Yb3+: NaYF4/MoS2-Ta2O5 are all characterized by XRD, SEM, EDX, and FT-IR techniques. The photocatalytic activity of beta-Tm3+, Yb3+: NaYF4/MoS2-Ta2O5 is examined through the photocatalytic hydrogen evolution from an aqueous methanol solution under near-infrared light irradiation. In addition, the influence of factors such as the mass ratio of beta-Tm3+, Yb3+: NaYF4 and MoS2-Ta2O5, the heat-treatment temperature, and the initial pH value of the solution on the photocatalytic hydrogen evolution activity of beta-Tm3+, Yb3+: NaYF4/MoS2-Ta2O5 is also studied. The results show that the photocatalytic hydrogen evolution activity of Ta2O5 can be greatly enhanced by adding the up-conversion luminescence agent (beta-Tm3+, Yb3+: NaYF4) and co-catalyst (MoS2). Furthermore, the beta-Tm3+, Yb3+: NaYF4/MoS2-Ta2O5 catalyst with a 40 : 100 mass ratio which was heat-treated at 450 degrees C for 60 min in an aqueous methanol solution at initial pH = 6.0 displays the highest photocatalytic activity under near-infrared light irradiation.