Enhanced photocatalytic activity of p-n-n heterojunctions ternary composite Cu2O/ZnO/Ag3PO4 under visible light irradiation

Synthesis and visible-light photocatalytic degradation of Ag3PO4/AgBr/hydroxyapatite ternary nanocomposites prepared from oyster shells

“…The key to improving the activity and stability of silver phosphate is to explore and construct new and efficient silver phosphate composite photocatalysts. To this end, researchers have developed a series of complexes by combining materials with silver phosphate, such as CeO 2 , 1 TiO 2 , 2 AgX, 3 GO, 4 Ti 3 C 2 , 5 CdWO 4 , 6 BiVO 4 , 7 ZnO, 8 CuO 9 and g-C 3 N 4 . 10 The results show that an effective composite material is beneficial to the transfer of photogenerated carriers in the material and can effectively inhibit electron–hole recombination, 11 thus improving the photocatalytic activity of the material.…”

Facile One-Pot In Situ Synthesis and Characterization of a Cu2O/Cu2(PO4)(OH) Binary Heterojunction Nanocomposite for the Efficient Photocatalytic Degradation of Ciprofloxacin from Aqueous Solution under Direct Sunlight Irradiation

“…For better clarification of the role of heterojunctions in the separation, transition, and recombination processes of electron–hole pairs in the nanocomposite, the band edge positions of Cu 2 (PO 4 )­(OH) and Cu 2 O structures can be predicted by the following formulas − where E CB , E VB , E e , and E g indicate the energies of conduction band (CB), valence band (VB), free electrons (∼4.5 eV), and band gap, respectively, and X shows the electronegativity of Cu 2 (PO 4 )­(OH) (∼6.45 eV) and Cu 2 O (∼5.33 eV). Therefore, the values of E VB and E CB for Cu 2 (PO 4 )­(OH) were calculated to be +3.12 and +0.77 eV, respectively, whereas the same for Cu 2 O were estimated to be +1.92 and −0.25 eV, respectively. , Accordingly, under sunlight irradiation, both Cu 2 (PO 4 )­(OH) and Cu 2 O compounds can be excited simultaneously and generate electrons and holes in the related CB and VB bands, respectively. Afterward, the photostimulated electrons will transfer from the CB of Cu 2 O to that of Cu 2 (PO 4 )­(OH); meanwhile, the photogenerated holes will migrate from the VB of Cu 2 (PO 4 )­(OH) to that of Cu 2 O.…”

“…On the other hand, cuprous oxide (Cu 2 O), as a p-type semiconductor with a narrow band gap of 2.0–2.2 eV, has demonstrated plentiful applications in the field of antibacterial, fuel cell, electrochemical, catalyst, solar cell, sensor, pigment, and especially photocatalysis. − Although the Cu 2 O structure exhibits strong visible-light absorption, the fast recombination of photogenerated electron–hole couples limits its usage as an individual photocatalyst. Therefore, when p-type Cu 2 O is paired with a n-type semiconductor such as Cu 2 (PO 4 )­(OH), a p–n heterojunction can be formed, resulting in a significantly enhanced photocatalytic performance. , …”

“…Recently, various approaches have been employed to improve the chemical and physical properties of nanomaterials. − In order to overcome the above-expressed drawbacks of Cu 2 (PO 4 )­(OH) and Cu 2 O structures, formation of a p–n heterojunction nanocomposite can be a potential solution to increase the photocatalytic efficiency. Prior to this, various heterojunction composites of Cu 2 (PO 4 )­(OH) and Cu 2 O materials have been fabricated, such as Cu 2 (OH)­PO 4 /g-C 3 N 4 , TiO 2 –Cu 2 (OH)­PO 4 , Cu 2 (OH)­PO 4 /reduced graphene oxide, Cu 2 (OH)­PO 4 /Cu, Cu 2 O/CdS/ZnO, Cu 2 O/ZnO/Ag 3 PO 4 , and Cu 2 O/Bi/Bi 2 MoO 6 . ,,,,− The combination of Cu 2 (PO 4 )­(OH) and Cu 2 O, due to the generation of the p–n junction heterostructure, can induce a synergistic effect between them and subsequently produce more strong oxidizing agents for outstanding photocatalytic performance under sunlight irradiation.…”

Current Developments in the Effective Removal of Environmental Pollutants through Photocatalytic Degradation Using Nanomaterials

“…Many factors are responsible for the deactivation of the photocatalysts, such as the loss of photocatalyst mass, especially during the washing/purification process. It has been reported that some amounts of rod-shaped ZnO stacking occur on Cu 2 O/Ag 3 PO 4 during filtration [204]. Leaching of dopants usually occurs during the reaction due to photoetching [205].…”