Construction of full-spectrum-driven Ag–g-C3N4/W18O49 heterojunction catalyst with outstanding N2 photofixation ability
Abstract
More than half of the solar spectrum is near infrared (NIR) light, which is seldom utilized in photocatalytic reactions. In this work, an Ag–g-C3N4/W18O49 heterojunction catalyst is prepared and used for full-spectrum-driven N2 photofixation from the UV to the NIR region for the first time. X-ray diffraction, N2 adsorption, UV-Vis-NIR spectroscopy, thermogravimetric analysis, photoluminescence, X-ray photoelectron spectroscopy and electrochemical impedance spectra were used to characterize the prepared catalysts. The result indicates that the as-prepared Ag–g-C3N4/W18O49 heterojunction catalysts display much higher N2 photofixation performance than that of individual W18O49 or Ag–g-C3N4, which should be due to the better separation rate of electron–hole pairs and more efficient light utilization. g-C3N4 is the active component in the catalyst for N2 photofixation. Ag loading promotes the separation rate of electron–hole pairs. W18O49 plays a role as light absorber in the full-spectrum to form more photogenerated electrons for recombining the holes in the g-C3N4 through “Z-scheme” mechanism. A possible electrons transfer route is proposed.