Synthesis of Au nanoparticle-decorated carbon nitride nanorods with plasmon-enhanced photoabsorption and photocatalytic activity for removing various pollutants from water

Abstract

Herein we have developed Au nanoparticle-decorated carbon nitride (Au-CN) nanorods as novel and efficient photocatalysts. Au-CN with different Au/CN precursor molar ratios (0.5%, 1% and 2%) have been prepared by a solvothermal-hydrothermal two-step method, where CN nanorods have diameters of 20–30nm and length of 0.5–1μm while Au nanoparticle have diameter of ∼13nm. Au-CN nanorods exhibit a broad photoabsorption from ultraviolet to near-infrared with edge at ∼790nm, revealing an obvious red-shift compared with g-C3N4 bulk (∼460nm), CN nanorods (∼715nm). Under visible-light irradiation, 1%Au-CN nanorods exhibit the highest photocatalytic activity, and they can degrade 98.2% rhodamine B (RhB), 77.2% 4-chlorophenol (4-CP), 83.9% tetracycline (TC) and reduce 43.6% hexavalent chromium (Cr(VI)) in 120min, higher than those by pure CN nanorods (70.3% RhB, 36.6% 4-CP, 54.6% TC, 23.1% Cr(VI)) and g-C3N4 bulk (31.5% RhB, 17.2% 4-CP, 36.9% TC, 11.8% Cr(VI)). Compared with CN nanorods, the obvious improvement of photocatalytic activity of 1%Au-CN nanorods should be attributed to the plasmon-enhanced photoabsorption and efficient separation of hole-electron pairs due to the introduction of Au nanoparticles.