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Nano Research

Article Title

Modulating the photoelectrons of g-C3N4 via coupling MgTi2O5 as appropriate platform for visible-light-driven photocatalytic solar energy conversion

Keywords

g-C3N4/MgTi2O5, visible-light, photocatalytic hydrogen production, CO2 reduction

Abstract

Graphitic carbon nitride (g-C3N4) has become an attractive visible-light-responsive photocatalyst because of its semiconductor polymer compositions and easy-modulated band structure. However, the bulk g-C3N4 photocatalyst has the low separation efficiency of photogenerated carriers and unsatisfied surface catalytic performance, which leads to poor photocatalytic performance. As for this, MgTi2O5 with high chemical stability, wide band gap and negative conduction band was used as a suitable platform for coupling with g-C3N4 to enhance charge separation and promoted the photoactivity. Different from common approaches, here, we propose an innovative method to construct g-C3N4/MgTi2O5 nanocomposites featuring “0 + 1 > 1” magnification effect to improve g-C3N4 photocatalytic performance under visible light irradiation. Additionally, compositing metal oxides of MgTi2O5 with g-C3N4 has proven to be a proper strategy to accelerate surface catalytic reactions in g-C3N4, and the photoinduced carriers were modulated to maintain thermodynamic equilibrium, which convincingly promotes the photocatalytic activity. The photocatalytic performance of the nanocomposites was measured by hydrogen production and CO2 reduction under visible light. The developed g-C3N4/MgTi2O5 nanocomposites with a 5 wt.% MgTi2O5 exhibits the highest H2 and CO yield under visible light and excellent stability compare to the other MgTi2O5 contents in composites. According to surface photo-voltage spectra, electrochemical CO2 reduction, photoluminescence, etc. The superior performance can be related to an enhanced electron lifetime, the promoted charge transfer and the increased electronic separation property of g-C3N4. Our work provides an approach to overcome the defect of pure g-C3N4, which accesses to composite with the second component matched well.

Graphical Abstract

Publisher

Tsinghua University Press

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