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Abstract
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Herein, for the first time, we reported the synthesis of a novel Z-scheme CoxNi1 xTiO3/CdS (x = 0.5) heterojunction
photocatalyst and the investigation of its visible-light-driven photocatalytic performance toward
degradation of methylene blue (MB). The developed photocatalyst was structurally characterized by applying XRay
diffraction analysis (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Xray
photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET), differential reflectance spectroscopy
(DRS), and photoluminescence (PL) techniques. The results indicated the formation of a highly porous structure
with improved visible light adsorption capacity, favorable for the catalytic activity. At an optimum condition of 10 mg/L of MB and 300 mg/L of catalyst, the ternary photocatalyst demonstrated a MB removal efficiency of 99
% after 75 min of the treatment process. The radical trapping experiments unveiled that hydroxyl and superoxide
radicals were two main reactive species formed under visible light, while the valance holes possessed an
insignificant role. The synergetic impact of the CoxNi1 xTiO3 (x = 0.5) and CdS on the photodegradation of MB
over the as-prepared CoxNi1 xTiO3/CdS (x = 0.5) photocatalyst through Z-scheme photocatalysis was indicated
by the results of the mechanism studies. The percentage impact of the treatment time, MB concentration, the
ratio of CoxNi1 xTiO3/CdS (x = 0.5), and the dosage of catalyst using analysis of the CCD modeling was obtained
as 47.04, 16.67, 7.22 and 0.87 %, respectively. Furthermore, the as-synthesized photocatalyst possessed high
recyclability and photostability with only a 3 % decline in activity after four repetitive cycles.
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