Synthesis of Silver Nanoparticles-Modified Graphitic Carbon Nitride Nanosheets for Highly Efficient Photocatalytic Hydrogen Peroxide Evolution

Abstract

As a promising metal-free photocatalyst, graphitic carbon nitride (g-C3N4) is still limited by insufficient visible light absorption and rapid recombination of photogenerated carriers, resulting in low photocatalytic activity. Here, we adjusted the microstructure of the pristine bulk-g-C3N4 (PCN) and further loaded silver (Ag) nanoparticles. Abundant Ag nanoparticles were grown on the thin-layer g-C3N4 nanosheets (CNNS), and the Ag nanoparticles decorated g-C3N4 nanosheets (Ag@CNNS) were successfully synthesized. The thin-layer nanosheet-like structure was not only beneficial for the loading of Ag nanoparticles but also for the adsorption and activation of reactants via exposing more active sites. Moreover, the surface plasmon resonance (SPR) effect induced by Ag nanoparticles enhanced the absorption of visible light by narrowing the band gap of the substrate. Meanwhile, the composite band structure effectively promoted the separation and transfer of carriers. Benefiting from these merits, the Ag@CNNS reached a superior hydrogen peroxide (H2O2) yield of 120.53 μmol/g/h under visible light irradiation in pure water (about 8.0 times higher than that of PCN), significantly surpassing most previous reports. The design method of manipulating the microstructure of the catalyst combined with the modification of metal nanoparticles provides a new idea for the rational development and application of efficient photocatalysts.

Schottky Junction Enhanced Photosynthesis of Hydrogen Peroxide by Ultrathin Porous Carbon Nitride Supported Ni Nanoparticles

“…Up to now, numerous approaches have been suggested to improve the photocatalytic efficiency of g-C 3 N 4 , including morphology tuning, , noble metal nanoparticles (NPs) loading, − defect control, − heterostructure construction, , etc. Among them, the transformation of BCN into thin-layer porous nanosheets through morphology tuning to improve electron transfer efficiency and expose more active sites is considered to be a simple and efficient modification method. − In addition, metal particles have been introduced onto semiconductor surfaces to capture photogenerated electrons by forming Schottky junctions, which inhibit charge recombination and enhances photocatalytic activity. , The difference in work function drives charge exchange at the interface, permitting the rectifying interface effect to alter the electron density of the metal and semiconductor .…”