Metal-organic framework [NH2-MIL-53(Al)] functionalized TiO2 nanotube photoanodes for highly stable and efficient photoelectrochemical cathodic protection of nickel-coated Mg alloy.

Autor: Yao, Huan, Zhang, Ruifeng, Wen, Yu, Liu, Yue, Yu, Gang, Xie, Zhi-Hui
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Zdroj: Journal of Materials Science & Technology; May2024, Vol. 182, p67-78, 12p
Abstrakt: • NH 2 -MIL-53(Al) functionalized TiO 2 nanotube photoanodes were prepared. • The photoanodes showed superior photoelectrochemical and PECCP performances. • Achieved 1.98 mA cm−2 photocurrent density under visible light irradiation. • Photo-induced OCP remained relatively stable within 35 h of light illumination. • A Z -scheme heterojunction between NH 2 -MIL-53(Al) and TiO 2 was verified. Metal-organic framework [MOF, i.e., NH 2 -MIL-53(Al)] modified TiO 2 (NMT) composite photoanodes were successfully prepared by hydrothermal synthesis and were used for the photoelectrochemical cathodic protection (PECCP) of nickel-plated magnesium alloy (Mg/Ni). Results showed that the synthesis temperature significantly impacted the morphology and PECCP performance of the NMT photoanodes. The NMT@150 photoanode prepared at a reaction temperature of 150 °C exhibited the best PECCP performance and produced a current density of 1980 μA cm−2 under visible light irradiation, which was 19.8 times higher than that of a single TiO 2 photoanode. The composite photoanode could polarize the open circuit potential of the coupled Mg/Ni electrode to -876 mV and remain relatively stable within 35 h. XPS and EPR tests showed that a Z -scheme heterojunction was formed between the NH 2 -MIL-53(Al) and TiO 2 nanotubes, allowing the photogenerated electrons to accumulate mainly on the conduction band of NH 2 -MIL-53(Al). The heterojunction greatly promoted the separation and transfer of photogenerated electron-hole in the NMT composite photoanode, significantly enhancing the PECCP performance for Mg/Ni. [Display omitted] [ABSTRACT FROM AUTHOR]
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