Synthesis and characterization of novel Ag2CO3/g-C3N4 composite photocatalysts with excellent solar photocatalytic activity and mechanism insight

Abstract

The photocatalytic performance of g-C3N4 is greatly limits by its inherent drawbacks, thus it is urgent to boost the photocatalytic activity of g-C3N4. Constructing Z-scheme composite photocatalysts has received great interesting in the photocatalysis field because of its great potential to promote the catalytic activity of photocatalysts by accelerating the separation of the photo-induced charge pairs. In this study, a series of Z-scheme Ag2CO3/g-C3N4composites were fabricated and characterized by X-ray diffraction patterns (XRD), inductively coupled plasma (ICP) spectroscopy, particle size analyzer, UV–vis diffuse reflectance spectra (DRS), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), high-resolution transmission electron microscopy (HRTEM), surface photovoltage spectroscopy (SPS),electron spin-resonance (ESR) spectroscopy and scavenger experiments. The corresponding photocatalytic performance toward methyl orange (MO) decolorization were investigated under the simulated sunlight irradiation. The results reveal that the Ag2CO3/g-C3N4composites display higher photocatalytic activity than the bare g-C3N4. The photocatalytic activity of the 7% molar ratio of Ag/g-C3N4 composite is more than 15 times of that of the bare g-C3N4. Based on the results of ESR and SPS, a Z-scheme separation and transfer scheme of the photo-induced charge pairs of Ag2CO3/g-C3N4 was proposed. This study sheds light on understanding the Z-scheme charge transfer mechanism.