Highly efficient photocatalytic performance of Cu2O@TiO2 nanocomposite: influence of various inorganic oxidants and inorganic anions

Abstract

This work offers the facile synthesis of Cu2O@TiO2 nanocomposites by solid state reaction towards the elimination of Acid-Red 8 (AR8) dye as a target pollutant model through the photocatalytic oxidation system. Another goal is to assess the capacity of various inorganic oxidants that act as alternative electron acceptor for Cu2O@TiO2 mediated photocatalytic oxidation. The prepared nanocomposite was analyzed by various analysis instruments, and their photocatalytic performance was systemically assessed with respect to the removal of AR8 dye. Upon irradiation, compared to pure Cu2O and pure TiO2 alone, the Cu2O@TiO2 has exhibited a higher photocatalytic performance which show that the combining TiO2 (n-type) with Cu2O (p-type) has been improved the electron mobility and subsequently decreasing the rate of electron-hole recombination. A kinetic study is confirmed that the degradation of AR8 has been obeyed the pseudo-first-order model. The perfection of the photocatalytic activity is achieved by using various inorganic oxidants such as; H2O2, Na2S2O8 and NaIO4 so as to produce an electron scavenger. Also, the apparent rate constant (kapp) and apparent quantum yield (Q app) are higher for all oxidants than without oxidants, while is lower in terms of electrical energy per order (EEO) and half-life time (t0.5). Periodate ion has considered the most efficient oxidant when compared with other oxidants for enhancing the photocatalytic activity via the formation of various reactive oxygen species. The degradation efficiency of these catalytic systems could be arranged in an ascending order: Cu2O@TiO2/ NaIO4 > Cu2O@TiO2/Na2S2O8 > Cu2O@TiO2/H2O2 > Cu2O > TiO2. Keywords: Photocatalytic oxidation, Cu2O@TiO2 nanocomposite, Inorganic oxidants, AR8 dye degradation, Electrical energy per order.