Construction of Ag3PO4/Ag4P2O7 nanospheres sensitized hierarchical titanium dioxide nanotube mesh for photoelectrocatalytic degradation of methylene blue.

Graphical abstract Ag 3 PO 4 /Ag 4 P 2 O 7 nanospheres were deposited on the surface of TiO 2 nanotube arrays by a hydrothermal method. The visible light photocurrent density of TiO 2 NTs/Ag 3 PO 4 /Ag 4 P 2 O 7 was 103.51 μA/cm2 and the photovoltage was −0.19 V/cm2. The TiO 2 NTs/Ag 3 PO 4 /Ag 4 P 2 O 7 showed the optimal photoelectrocatalytic removal efficiencies of methylene blue. Highlights • Ag 3 PO 4 /Ag 4 P 2 O 7 nanospheres were deposited on TiO 2 nanotube arrays/Ti mesh by a hydrothermal method. • The TiO 2 NTs/Ag 3 PO 4 /Ag 4 P 2 O 7 photoelectrode showed the excellent photoelectrochemical properties. • The PEC mechanism of TiO 2 NTs/Ag 3 PO 4 /Ag 4 P 2 O 7 photocatalysts was proposed. Abstract Ag 3 PO 4 /Ag 4 P 2 O 7 nanospheres were deposited on the surface of TiO 2 nanotube arrays/Ti mesh by the hydrothermal method, and the cetyltriethylammnonium bromide (CTAB) addition amount significantly influenced the morphology, phase composition, solar absorption, photoelectric conversion and photoelectrocatalytic (PEC) degradation of methylene blue (MB). The results indicated that the sample prepared with the CTAB addition of 0.025 g showed the optimal visible light photocurrent density (103.51 μA/cm2), photovoltage (−0.19 V/cm2) and PEC efficiency (99.39%) for MB decomposition. The influence factors of PEC performances including external voltage and electrolyte concentration were further explored. Beside, the PEC mechanism of TiO 2 NTs/Ag 3 PO 4 /Ag 4 P 2 O 7 was tentatively proposed. The excellent photoelectrochemical activity of the three dimensional (3D) TiO 2 NTs/Ag 3 PO 4 /Ag 4 P 2 O 7 photoelectrode would drive it prospective applications in solar cells and waste-water treatment. [ABSTRACT FROM AUTHOR]