Design and synthesis of robust Z-scheme ZnS-SnS2 n-n heterojunctions for highly efficient degradation of pharmaceutical pollutants: Performance, valence/conduction band offset photocatalytic mechanisms and toxicity evaluation

Heterojunction photocatalysts for degradation of the tetracycline antibiotic: a review

“…The first breakdown pathway and relative intermediates are shown in Scheme 1 . The aromatic ring of the tetracycline molecule is easy to undergo hydroxylation after the attack by OH · , thus forming isomers A1a and A1b with m/z = 461 (Xia et al 2020 ). Product A2 (m/z = 433) is generated when the N-methyl group of the A1a fragment is damaged by h + .…”

“…Xia et al ( 2020 ) also indicated that the double bond between C2 and C13 of tetracycline could be attacked by h + radical, inducing the cleavage of unsaturated bond and forming an amino-free fragment F9 (m/z = 389). A series of processes including loss of -N(CH 3 ) 2 -CHO group, dihydroxylation, and demethylation of F9 yield products F10 (m/z = 346), F11 (m/z = 304), and F12 (m/z = 258).…”

Two-Dimensional ZnS/SnS2 Heterojunction as a Direct Z-Scheme Photocatalyst for Overall Water Splitting: A DFT Study

“…ZnS/SnS 2 heterojunctions have also been reported [ 38 , 39 , 40 , 41 , 42 , 43 ], as shown in Table 1 . However, different research groups obtained different results.…”

“…In a heterojunction, photogenerated electrons migrate from the CB of ZnS to the CB of SnS 2 , and photogenerated holes transfer from the VB of SnS 2 to the VB of ZnS, which realizes the separation of photogenerated electron-hole pairs. Still others though that ZnS/SnS 2 belongs to the direct Z-scheme heterojunction, and their descriptions for energy band alignments of ZnS and SnS 2 are controversial [ 42 , 43 ]. Derikvandi et al [ 42 ] believed that both the CB and VB of SnS 2 are lower than the corresponding bands of ZnS, while Xia et al [ 43 ] believed that both the CB and VB of SnS 2 are higher than the corresponding bands of ZnS.…”

“…Still others though that ZnS/SnS 2 belongs to the direct Z-scheme heterojunction, and their descriptions for energy band alignments of ZnS and SnS 2 are controversial [ 42 , 43 ]. Derikvandi et al [ 42 ] believed that both the CB and VB of SnS 2 are lower than the corresponding bands of ZnS, while Xia et al [ 43 ] believed that both the CB and VB of SnS 2 are higher than the corresponding bands of ZnS. Hence the interlayer charge transfer in the heterojunction is opposite in their studies, and the sites of redox reaction are also different.…”