Novel polyaniline/tungsten trioxide@metal–organic framework nanocomposites for enhancing photodegradation of 4-nitrophenol

Abstract

Novel photocatalysts polyaniline/tungsten trioxide (P/W), polyaniline/tungsten trioxide @zeolitic imidazolate frameworks, (P/W@ZIF-8) and polyaniline/tungsten trioxide@ Zr(IV) aminoterephthalate metal–organic frameworks (P/W@UiO-66-NH2 MOFs) were successfully synthesized via the in-situ growth of polyaniline, ZIF-8, and UiO-66-NH2 MOFs onto the tungsten trioxide nanoparticle. The synthesized photocatalysts have been characterized using XRD, FT-IR, FESEM, TEM, EDX, BET, UV–vis and PL techniques. The P/W, P/W@ZIF-8 and P/W@UiO-66-NH2 composites show the best degradation efficiency for 4-nitrophenol (4-NP) with an apparent rate constants value of 0.01439, 0.0319 and 0.0500 min−1, respectively, that is 19, 42.3 and 66.3 times as greater as that of pristine WO3 (7.54 × 10−4 min−1). Typically, 20 ppm of the 4-NP solution was degraded completely and 95.8% of the carbon content had been mineralized in 180 min at 25 °C using 0.5 g/L of the P/W@UiO-66-NH2 nanocomposite. The remarkable improvement of catalytic activity and photostability could be due to the synergetic effect between tungsten trioxide, polyaniline, and metal–organic frameworks. Based on the quenching tests, •OH and •O2− were referred to be the main effective species. Reusability experiments of photocatalyst demonstrated that the photocatalyst displays excellent stability and reusability.