Synthesis of a new porous Cu2O@Cu4(SO4) (OH)6·2H2O core-shell thermocatalyst by in situ etching for efficient catalytic degradation of dye under dark condition

Abstract

A new porous Cu2O@Cu4(SO4) (OH)6·2H2O core-shell low temperature thermocatalyst was synthesized via in situ reaction and corrosion on the surface of Cu2O core by using Na2S2O3 as the alkali. The formation mechanism of the catalyst was investigated and the function of Na2S2O3 has been explored. OH− groups were easily adsorbed on the surface of Cu2O core with positive charged as reactive sites, Cu4(SO4) (OH)6·2H2O crystals were generated on the surface. In the synthesis reaction, Na2S2O3 played multiple roles. (1) hydrolyze to produce OH− group; (2) dismutate to generate SO42−; (3) corrode Cu2O core to form holes. The morphological, structural, optical and electrochemical properties of Cu2O@Cu4(SO4) (OH)6·2H2O catalyst were investigated in detail. The results revealed that the core-shell catalyst exhibits stronger light absorption, better charge separation efficiency and faster migration of active species. Cu4(SO4) (OH)6·2H2O shows strong thermal radiation effect, this makes it easier to gather enough heat energy at room temperature, so electrons at the VB can promote to the CB by absorbing environmental heat energy. Under dark condition the Z-scheme Cu2O@Cu4(SO4) (OH)6·2H2O thermocatalyst can degrade 98.9% acid orange 7 (250 ​mg/L) in 2h. Hence, this core-shell catalyst is an efficient low temperature thermocatalyst, implying a potential “day-night” thermocatalyst for the degradation of dye wastewater.