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Effective combination of CuFeO2 with high temperature resistant Nb-doped TiO2 nanotube arrays for CO2 photoelectric reduction

Zhang, Liqiang, Cao, Huazhen, Lu, Yueheng, Zhang, Huibin, Hou, Guangya, Tang, Yiping, Zheng, Guoqu
Journal of colloid and interface science 2020 v.568 pp. 198-206
X-ray diffraction, X-ray photoelectron spectroscopy, absorption, alloys, argon (noble gases), carbon dioxide, cathodes, copper, crystallization, ethanol, heat treatment, iron, liquids, microstructure, nanotubes, oxidation, photocatalysis, reflectance spectroscopy, scanning electron microscopy, semiconductors, temperature, titanium dioxide, transmission electron microscopy
Herein, we report a simple approach to synthesize CuFeO₂/TNNTs photocathodes composed of high-temperature resistance n-type Nb-doped TiO₂ nanotube arrays (TNNTs) and p-type CuFeO₂ for CO₂ reduction. TNNTs were prepared by anodic oxidation on TiNb alloy sheets and CuFeO₂/TNNTs were then prepared by coating precursor liquid onto TNNTs followed by heat treatment in argon atmosphere. The microstructures of CuFeO₂/TNNTs and TNNTs before and after heat treatment were investigated by SEM and TEM. The phase compositions of CuFeO₂/TNNTs were studied by XRD and XPS, and the light absorption performance were tested by UV–vis diffuse reflectance spectrum. Results show that TNNTs exhibit a regular nanotube arrays structure and this structure is well remained after the calcination at 650 °C. In addition, TNNTs show similar semiconductor properties to n-type TiO₂, which enables them to be integrated with p-type CuFeO₂ to obtain composite photocathodes with a p-n junction. The synthesized CuFeO₂/TNNTs photocathode is well crystallized because no other crystalline iron or copper compounds are included in the prepared photocathode. Furthermore, the photocathode shows high light absorption and fast carrier transport due to the appropriate band gap and p-n junction. As a result, high photoelectrocatalytic CO₂ reduction performance with high selectivity to ethanol is obtained on this photocathode.