Constructing S-scheme heterojunctions with tunable interfacial oxygen vacancy via UiO-66-NH2-derived ZrO2-x for efficient photocatalytic performance

Defects engineering is significant for photocatalytic environment remediation. To this end, visible-light-driven α-Fe 2 O 3 /ZrO 2-x S-scheme heterojunction photocatalysts with optimal oxygen vacancy (O v ) defects are successfully synthesized via a two-step method. Compared with pristine UiO-66-NH 2 -derived ZrO 2-x and α-Fe 2 O 3 , the heterojunction photocatalysts exhibit a wider range of visible light response and higher efficiency in separating photogenerated electron–hole pairs. Among them, the 5% α-Fe 2 O 3 /ZrO 2-x sample shows the best photocatalytic performance to the degradation of tetracycline (TC) (89.3%), in which the pseudo-first-order kinetic rate constants are 8.20 and 16.75 times that of pristine ZrO 2-x and α-Fe 2 O 3 , respectively. The outstanding photocatalytic degradation efficiency can be attributed to both the narrow-bandgap ZrO 2-x with visible light response and the formation of α-Fe 2 O 3 /ZrO 2-x S-scheme heterojunctions. During the formation of heterojunctions, the concentration of oxygen vacancies (O v ) at the interface of α-Fe 2 O 3 /ZrO 2-x decreases monotonically with the increasing loading of α-Fe 2 O 3 , thereby altering the electronic structure of the photocatalyst and forming the heterojunction firmly. In addition, the high stability implies the potential applications in fields of environment.