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In this work, a (ZnO)/(Cu-doped ZnO) core/shell nanorods array was fabricated by a two-step method: ZnO hydrothermal synthesis followed by encapsulation via a dip-coating process. The effects of the Cu dopant concentration on the structural, electrical and optical properties of the nanorods were studied. The SEM images showed that the encapsulation increased the nanorods average diameter from ~40 to ~60 nm. All ZnO core/shell nanorods showed a hexagonal wurtzite structure with no trace of a Cu oxide phase. A peak shift was observed in the XRD pattern, indicating the better Cu+ substitution into the Zn sites. The I–V measurements also showed that Cu doping up to 4.5 at.% decreased the samples resistance, which could be attributed to the +1 valance state of the Cu ions. It was also found that Cu doping increased the UV photoresponsivity of the photodetectors made by Cu:ZnO.

Herein, Cu was incorporated into ZnO lattice to reduce its band gap as well as to extend its visible radiation response. The obtained Cu-ZnO was continuously integrated with g-C 3 N 4 to create Cu-ZnO/g-C 3 N 4 Z -direct scheme photocatalyst for advanced atrazine removal. Radical scavenging experiments have been also conducted to clearly figure out photocatalytic mechanism for degradation of atrazine by the synthesized photocatalyst. The synthesized Cu-ZnO only utilized the generated h+ for atrazine degradation (direct and indirect via formation hydroxyl radicals (•OH)) and the g-C 3 N 4 only utilized the generated e− for atrazine degradation (indirect via reaction with O 2 to form superoxide anion, which needed to continuously react with H 2 O to form •OH). Therefore, the photocatalytic atrazine degradation by synthesized Cu-ZnO material was greater than that by synthesized g-C 3 N 4 material. Cu-ZnO/g-C 3 N 4 utilized both generated e− and h+ for degradation of atrazine. Thus, the photocatalytic atrazine degradation by the synthesized Cu-ZnO/g-C 3 N 4 was greater than those of single g-C 3 N 4 or Cu-ZnO materials. Finally, the conducted recycling experiments indicated great stability of synthesized Cu-ZnO/g-C 3 N 4 during long-term atrazine degradation process opening new era for application of the material in practical systems. Unlabelled Image • Cu doped into ZnO lattice to reduce its band gap and to extend its visible radiation response. • Cu-ZnO was successfully combined with g-C 3 N 4 to establish Z direct scheme system. • Z -scheme prevented fast recombination of e− and h+ and maintained their re-dox potential. • The Cu-ZnO/g-C 3 N 4 utilized both generated e− and h+ for degradation of atrazine. • The Cu-ZnO/g-C 3 N 4 showed excellent activity and stability during long-term photocatalysis. [ABSTRACT FROM AUTHOR]

• Successfully doped Cu into ZnO lattice to enhance its photocatalytic activity. • Cu dopant prevented recombination of photo-excited e− and h+ of the ZnO. • The Cu-ZnO exhibited excellent photocatalytic degradation of monocrotophos pesticide. • The optimal mole ratio of Cu/ZnO in the Cu-ZnO for degradation of monocrotophos was 3%. • The optimal pH for the photocatalytic degradation of monocrotophos was pH 7. In the work, we successfully synthesized Cu doped ZnO materials for photocatalytic degradation of monocrotophos pesticide (MCP). The used Cu metal doped into the ZnO matrix created an intermediate band to excite electron from valence band (VB) to conduction band (CD) of the ZnO leading to increase in optical absorption, decrease in band gap as well as photocatalytic performance of the material. Hence, the synthesized photocatalyst showed intense activity for photocatalytic degradation of MCP into CO 2 , H 2 O and harmless inorganic ions even under visible radiation. We also investigated that the 3Cu-ZnO photocatalyst, which the weight ratio of Cu/ZnO was 3 wt%, showed the highest MCP degradation efficiency among these synthesized Cu-ZnO. The excess dopants tended to form CuO existing on ZnO surface. The formed CuO acted as a center for recombination of produced electrons and holes resulted in decrease in photocatalytic performance of the Cu-ZnO. Finally, we investigated that the optimal pH for the degradation of MCP by the synthesized Cu doped ZnO photocatalyst was pH 7. [ABSTRACT FROM AUTHOR]