Black Si-doped TiO(2) nanotube photoanode for high-efficiency photoelectrochemical water splitting

Black Si-doped TiO(2) (Ti–Si–O) nanotubes were fabricated through Zn metal reduction of the Ti–Si–O nanotubes on Ti–Si alloy in an argon atmosphere. The nanotubes were used as a photoanode for photoelectrochemical (PEC) water splitting. Both Si element and Ti(3+)/oxygen vacancies were introduced into the black Ti–Si–O nanotubes, which improved optical absorption and facilitated the separation of the photogenerated electron–hole pairs. The photoconversion efficiency could reach 1.22%, which was 7.18 times the efficiency of undoped TiO(2). It demonstrated that a Si element and Ti(3+)/oxygen vacancy co-doping strategy could offer an effective method for fabricating a high-performance TiO(2)-based nanostructure photoanode for improving PEC water splitting.