Preparation of high proportion of Z-scheme Er~(3+):Y_3Al_5O_(12)@Nb_2O_5/Pt/ In_2O_3 composite for enhanced visible-light driven photocatalytic hydrogen production

摘要

Although the Z-scheme photocatalysts have high photocatalytic activity, it is difficult to obtain a high proportion of Z-scheme photocatalytic system. In this paper, it is reported for the first time that a high proportion of Z-scheme Er~(3+)∶Y_3Al_5O_(12)@Nb_2O_5/Pt/In_2O_3 composite photocatalyst can be prepared by coating-demoulding (C-D) method. In this Z-scheme photocatalyst, Pt nanoparticles as conductive channels are fixed between Er~(3+):Y_3Al_5O~(12)@Nb_2O_5 and In_2O_3. Er~(3+)∶Y_3Al_5O_(12) as up-conversion luminescence agent can provide enough ultraviolet-lights to activate wide band-gap Nb_2O_5. The as-prepared samples are characterized by X-ray dif-fractometer (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray (EDX) spectroscopy, X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectra (DRS), fourier transform infrared spectra (FT-IR), photoluminescence (PL) spectra and related electrochemical tests. Further, the effects of heat-treatment temperature, heat-treatment time and used times on the photocatalytic hydrogen production activity of C-D Z-scheme Er~(3+)∶Y_3Al_5O_(12)@Nb_2O_5/Pt/In_2O_3 composite are studied in detail. The experimental results showed that the photocatalytic activity of C-D Z-scheme Er~(3+)∶Y_3Al_5O_(12)@ Nb_2O_5/Pt/In_2O_3 composite is the highest in photocatalytic hydrogen production when heat-treatment temperature and time are 500 °C and 1.0 h, respectively, and that the high photocatalytic activity can be maintained within four cycles. It can be confirmed that the C-D method can effectively combine different photocatalyst particles in predicted order, greatly enhancing the proportion of highly active Z-scheme photocatalyst particles.