A highly efficient bifunctional Z-scheme photocatalyst with spatially-separated and synergistically-enhanced adsorption and photodegradation

Adsorption-enhanced photodegradation and its unique kinetics are studied in a bifunctional Z-scheme photocatalyst. MoS 2 nanoflakes are selectively deposited on the edges of TiO 2 nanosheets to form an edge-connected MoS 2 /Au/TiO 2 Z-scheme heterostructured photocatalyst, with rapid pollutant adsorption on MoS 2 surfaces and subsequent degradation on TiO 2 surfaces. The spatial separation of two components promotes the formation of Z-scheme charge transfer and maintains the effective bifunctions. As a result, the optimal system (10 %MoS 2 /Au/TiO 2 ) could remove up to 90 % of pollutant within 30 mins and subsequently eliminates the residue to a level below ppm. Detailed study on the synergistic effects of adsorption and photodegradation indicates that the system exhibits an adsorption-enhanced photodegradation due to the pre-concentration effect by MoS 2 and a surface-diffusion mechanism of pollutant molecules migrating from MoS 2 to TiO 2 . This work provides a novel strategy in designing the bifunctional photocatalyst for effective water treatment. • An effective bifunctional Z-scheme photocatalyst is fabricated for water treatment. • The adsorption sites are spatially separated from photodegradation sites. • The designed system exhibits an adsorption-enhanced photodegradation. • The enhancement is induced by a surface-diffusion mechanism.