S-scheme heterojunction/Schottky junction tandem synergistic effect promotes visible-light-driven catalytic activity

Designing photocatalysts with high light utilization and efficient photogenerated carrier separation for pollutant degradation is one of the important topics for sustainable development.In this study,hierarchical core–shell materialα-Fe_(2)O_(3)@ZnIn_(2)S_(4)with a step-scheme(S-scheme)heterojunction is synthesized by in situ growth technique,and MXene Ti_(3)C_(2)quantum dots(QDs)are introduced to construct a double-heterojunction tandem mechanism.The photodegradation efficiency ofα-Fe_(2)O_(3)@ZnIn_(2)S_(4)/Ti_(3)C_(2)QDs to bisphenol A is 96.1%and its reaction rate constant attained 0.02595 min^(−1),which is 12.3 times that of pureα-Fe_(2)O_(3).Meanwhile,a series of characterizations analyze the reasons for the enhanced photocatalytic activity,and the charge transport path of the S-scheme heterojunction/Schottky junction tandem is investigated.The construction of the S-scheme heterojunction enables the photo-generated electrons ofα-Fe_(2)O_(3)and the holes of ZnIn2S4 to transfer and combine under the action of the reverse built-in electric field.Due to the metallic conductivity of Ti_(3)C_(2)QDs,the photogenerated electrons of ZnIn_(2)S_(4)are further transferred to Ti_(3)C_(2)QDs to form a Schottky junction,which in turn forms a double-heterojunction tandem mechanism,showing a remarkable charge separation efficiency.This work provides a new opinion for the construction of tandem double heterojunctions to degrade harmful pollutants.

Adoptively transferred donor IL-17-producing CD4^(+) T cells augment, but IL-17 alleviates, acute graft-versus-host disease

The role of IL-17 and IL-17-producing CD4^(+) T cells in acute graft-versus-host disease(GVHD)has been controversial in recent mouse and human studies.We carried out studies in a murine acute GVHD model of fully major histocompatibility complex-mismatched myeloablative bone marrow transplantation.We showed that donor wild-type CD4^(+) T cells exacerbated acute GVHD compared with IL-17−/−CD4^(+) T cells,while IL-17 reduced the severity of acute GVHD.The augmentation of acute GVHD by transferred donor IL-17-producing CD4^(+) T cells was associated with increased Th1 responses,while IL-17 decreased the percentages of Th1 cells in the GVHD target organs.Furthermore,IL-17 reduced the infiltration of macrophages into the GVHD tissues.In vitro study showed that IL-17 could downregulate Th1 responses,possibly through inhibiting IL-12 production by donor macrophages.Depletion of macrophages in vivo diminished the protective effect of IL-17.Our results demonstrated the differential roles of adoptively transferred donor IL-17-producing CD4^(+) T cells and IL-17 in the same acute GVHD model.