Graphene supported βNaYF4:Yb3+,Tm3+ and N doped P25 nanocomposite as an advanced NIR and sunlight driven upconversion photocatalyst

A new photocatalytic nanocomposite consisting of upconversion material (β-NaYF4:Yb3+,Tm3+), N doped P25 (P(N)), and graphene (GP) has been fabricated successfully and shown to be an advanced photocatalyst under the near infrared (NIR) and sunlight irradiation. During the preparation process, β-NaYF4:Yb3+,Tm3+ and P(N) were simultaneously loaded on GP and they were closely attach to each other. The light absorption range of P(N) matches well with the converted light emission peaks of β-NaYF4:Yb3+,Tm3+, resulting in P(N) can absorb the converted light sufficiently for photocatalysis. The introduced GP not only act as the support material, but also enhances the light absorption and photogenerated electron–hole pairs’ separation. Photocatalytic activity measurements of the new photocatalyst under the NIR and simulated sunlight irradiation was improved compared with those of pure and GP supported P(N). The upconversion efficiency related photocatalytic activity confirms the significant role of upconversion materials. Overall, this investigation may provide new insights in preparing new photocatalysts by coupling with optical function materials to make sufficient use of sunlight for practical applications.