Enhanced photodegradation of toxic volatile organic pollutants using Ni-doped graphitic carbon nitride under natural solar light

摘要

In this study, nickel-doped graphitic carbon nitride (Ni-gC(3)N(4)) was synthesized via facile thermal condensation and explored as a visible-light responsive photocatalyst for degrading volatile organic compounds (VOCs). Remarkably, Ni-gC(3)N(4) with 2.5 wt% of Ni loading was capable of removing 98.6% of VOCs within 120 min under solar light. Moreover, the pseudo-first-order kinetic rate for Ni-gC(3)N(4) was found to be approximately twice as high as that of an undoped sample. The Ni doping promoted visible light harvesting and charge separation efficiency, and endowed photoexcited electrons (e(-)) with an enhanced reduction capacity, as demonstrated by X-ray photoelectron spectroscopy analysis, the photoluminescence (PL), the photocurrent (PC) and UV-Vis optical characterization. In addition, recycling test results showed that Ni-gC(3)N(4) exhibited excellent stability and recyclability. The influencing factors such as solution pH, the initial concentration of VOCs, and co-existing inorganic anions were investigated in detail. Results from radical scavenger experiments revealed that O-2(-), OH and h(+) were involved in the photocatalytic degradation process by using Ni-gC(3)N(4)/solar-light system. This study can contribute to the development of high-performance catalysts for removing toxic organic pollutants from wastewaters.