Enhanced photoelectrochemical performances in photocatalytic pollutant degradation and water splitting by direct Z-scheme Bi2Sn2O7/TiO2 NTAs.

The construction of ternary metal oxide to improve photoelectrochemical performances of TiO 2 photocatalysts is the hot topic in environmental and resource applications. Herein, Bi 2 Sn 2 O 7 nanoparticles were deposited on TiO 2 nanotube arrays (TiO 2 NTAs) by the solvothermal technology only by changing reagent concentration. The solar absorption region of TiO 2 NTAs was obviously extended into visible light after Bi 2 Sn 2 O 7 sensitization, and the photoelectric performance was also significantly improved. The high visible light photocurrent density and photovoltage achieved 30.24 μA/cm2 and -0.19 V, and the interface resistance was reduced that benefited the rapid electron transportation. The photocatalytic performances of methyl orange (MO), rhodamine b (RhB), methylene blue (MB) and Cr (VI) removal were enhanced, and 63.76%, 77.34%, 100% and 100% of these pollutants were photoremoved under solar irradiation. Moreover, the construction of direct Z-scheme Bi 2 Sn 2 O 7 /TiO 2 NTAs heterojunction was beneficial to the photoelectron transfer and active radical formation, and the experimental results indicated that •OH and •O 2 - were the decisive species for the dye degradation. The samples also exhibited outstanding photocatalytic water splitting for H 2 evolution, and the high efficiency (306.36 μmol·cm−2·h−1) and stability were confirmed. The excellent photocatalytic performances of the Bi 2 Sn 2 O 7 /TiO 2 NTAs photoelectrodes showed extensive potential applications in environmental pollution and green resource exploitation. [ABSTRACT FROM AUTHOR]