Degradation of Pollutants and Photocatalytic H₂ Evolution Using Carbon Nanotube/Ag Nanoparticle-Modified BaTiO₃ Nanoparticles

Abstract

A ternary nanocomposite, BaTiO 3 −CNT/Ag, was synthesized via a coprecipitation method to function as a photocatalyst for pollutant degradation and H 2 production through a water-splitting reaction. The successful preparation of the nanocomposite and the enhancement of its morphological properties were confirmed through Raman spectroscopy, X-ray diffraction/photoelectron spectroscopy (XRD/XPS), and scanning/transmission electron microscopy (SEM/TEM) studies. Utilizing transient photocurrent, photoluminescence (PL) spectroscopy, UV−visible diffuse reflectance spectroscopy (DRS), Mott−Schottky, and electrochemical impedance spectroscopy (EIS) tests, it was determined that the incorporation of carbon nanotube (CNT) and Ag into BaTiO 3 led to a promotion of charge separation efficiency up to 15 times, a decrease in the bandgap energy from 3.12 to 2.85 eV, larger band bending, lower electron/ hole recombination, and extensive lower internal resistance. In photodegradation-related studies, the response surface methodology (RSM) method was performed for experimental design to optimize the amounts of photocatalyst dosage, irradiation time, and initial dye concentration, yielding optimal values of 0.681 g/L, 67.5 min, and 1 mg/L, respectively. The sample showed outstanding photocatalytic efficiency in the degradation of different organic water pollutants, coupled with remarkable stability and reusability, as evidenced by a four-run cyclic experiment. Finally, the evaluation of H 2 production revealed a remarkable amount of 542.4 μmol/g•h for the ternary nanocomposite, which is about 5 times higher than that of the pure BaTiO 3 sample. This research provides thorough insight into the synthesis of a ternary nanocomposite that extremely enhances the charge transfer abilities and, therefore, boosts the photocatalytic H 2 production and photodegradation of pollutants.