Ag-Modified g-C₃N₄ Prepared by a One-Step Calcination Method for Enhanced Catalytic Efficiency and Stability

Abstract

Ag-decorated g-C 3 N 4 (denoted as Ag/CN- x ) was prepared by a one-step calcination method, and the influences of calcination time on structure, morphology, surface composition, photocatalytic performance, and catalytic reduction activity of the prepared Ag/CN- x samples were investigated. The tests showed that the Ag/CN-8 prepared through by calcination for 8 h exhibited the best photocatalytic degradation efficiency of methyl orange (98.7% within 2 h) and the best catalytic reduction property of 4-nitrophenol (100% within 70 s). Meanwhile, these Ag/CN- x samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectra (DRS), photoluminescence (PL), photocurrent response, and electrochemical impedance spectroscopy (EIS) Nyquist plots. It was found that the Ag/CN-8 prepared through calcination for 8 h had a higher specific surface area, higher dispersibility of silver nanoparticles (Ag NPs), the widest range of visible light response, and the lowest photogenerated electron–hole recombination rate. The results of the trapping experiments indicated that a superoxide radical plays a major role. Moreover, a possible mechanism of photocatalytic degradation in methyl orange and catalytic reduction 4-nitrophenol was proposed.

Fe3O4-Loaded g-C3N4/C-Layered Composite as a Ternary Photocatalyst for Tetracycline Degradation

“…As a typical magnetic material, Fe 3 O 4 has been widely used in the synthesis of magnetic photocatalysts due to its good stability, low cost, good magnetism, and environmental friendliness. In addition, it can also be used as a good redox medium to store electrons and further improve photocatalytic performance. − …”

Constructing Ternary Photocatalyst Ag/Ni(OH)2/g‐C3N4 for Efficient Photocatalytic Hydrogen Production

“…As can be seen from Figure 1, the pristine g-C 3 N 4 and AxNyÀ CN display two characteristic peaks at 13.4°and 27.5°, which can be indexed as the (100) and (002) crystal plane of g-C 3 N 4 . [30] As for the AxNyÀ CN, the characteristic peaks at 38.1°, 44.3°, 64.4°and 77.4°can be indexed as (111), ( 200), (220), and (311) crystal plane of metallic Ag, respectively, while the characteristic peaks at 19.5°, 33.2°, and 59.2°belong to the (001), (100) and (110) crystal plane of Ni(OH) 2 , respectively. [31,32] Moreover, as far as A5NyÀ CN samples are concerned (Figure 1a), with the increase of Ni(OH) 2 amounts, the diffraction intensities of Ni(OH) 2 become stronger.…”

Photocatalytic Reduction of Aqueous Nitrate with Hybrid Ag/g-C3N4 under Ultraviolet and Visible Light

“…Pure g-C 3 N 4 shows the highest relative emission intensity, with evidence of quenching as silver loading is increased in the hybrid Ag/g-C 3 N 4 materials. The emission quenching observed in the hybrid Ag/g-C 3 N 4 is likely due to charge transfer from the g-C 3 N 4 semiconductor to the silver metal nanoparticle, preventing radiative recombination of the photogenerated excited state. − Note, however, that extensive quenching of the PL is not observed until the highest two Ag loadings, suggesting that many emissive states have insufficient mobility to encounter an Ag particle during their lifetime. , …”