Ion‐Exchange Synthesis of ZnO/ZnSe/CdSe Core/Shell Heterostructured Nanowire Photoanodes toward High‐Performance Photocathodic Protection of 304 Stainless Steel

Abstract

Photocathodic protection technology is emerging to harvest solar light for electrochemical corrosion protection of metals. Herein, ZnO/ZnSe/CdSe heterostructured nanowire arrays were synthesized on conductive glass substrates by a two-step ionexchange reaction in ZnO nanowire arrays. The as-prepared ZnO/ZnSe/CdSe core/shell nanostructure was unveiled by XRD, SEM, TEM, EDAX elemental mapping, and XPS analyses. The ZnO/ZnSe/CdSe ternary heterojunction photoanode exhibits a considerably enhanced absorption for visible light and a significantly increased separation, transfer, and collection efficiencies for photogenerated charges. When working as photoanodes, the as-deigned ZnO/ZnSe/CdSe heterostructured nanowire arrays demonstrates a superior photocathodic protection performance for the coupled 304 stainless steel under illumination with AM 1.5G. Results and DiscussionZnO/ZnSe/CdSe core/shell heterostructured nanowire array photoanodes were prepared on FTO substrates by sequential [a] Y.

Interfacial anion vacancy engineered graphitic carbon nitride photoelectrode for promoting charge separation

“…28,43 The band gaps were observed to be 3.12, 2.12 and 2.06 eV for ZnO, ZnSe and g-C 3 N 4 , respectively. 24,28,42,43 The research findings are consistent with the literature. 43–48…”

“…2(a), which is ascribed to the formation of the ZnSe shell on ZnO nanorods. 23–27 It depicts the successful formation of ZnSe on ZnO and the co-existence of ZnO and ZnSe phases. Interestingly, a dominant peak was observed at around 1580 cm −1 for the g-C 3 N 4 loaded electrode.…”

“…The increase in the photocurrent density is ascribed to the enhanced visible light absorption in the binary and ternary junctions. 24,26 In the case of the ternary junction, the increase in the photocurrent density is ascribed to the formation of selenium vacancies at the interface, which act as active sites for the recombination of electrons of g-C 3 N 4 and holes of ZnSe. Fig.…”

“…The increase in the photocurrent density is ascribed to the enhanced visible light absorption in the binary and ternary junctions. 24,26 In the case of the ternary junction, Fig. 5 LSV (a), I-t curve (b), and CV in the dark (c) and under illumination (d) of ZnO (black), ZnO@ZnSe (blue) and ZnO@ZnSe@g-C 3 N 4 (red) photoelectrodes.…”

“…[16][17][18][19][20] Due to the exceptional advantages of one dimensional (1D) materials like high specific surface area and pore volume, effective photon absorption and scattering, less reflectivity, and fast and long-distance charge transport, 21,22 we synthesized ZnO nanorods and used them as a sacrificial template for the formation of a ZnO@ZnSe core-shell. [23][24][25][26][27] Together with the above-mentioned properties, interfacial selenium vacancies (Se V ) are introduced upon the addition of g-C 3 N 4 onto ZnSe semiconducting photocatalysts. As the reactive center, it decreases the CB level of ZnSe for the sequential transport of electrons among the semiconductors, thus leading to the effective separation of photogenerated charge carriers in the ZnO@ZnSe@g-C 3 N 4 ternary junction.…”