A core–double shell heterostructure Co9S8@Co9S8@MoS2-0.5 with multiple interfaces and a tunable electronic structure was constructed as an efficient tri-functional electrocatalyst.

Abstract

Heterostructure composites are promising materials in photocatalytic hydrogen evolution due to their advantage on promoting photogenerated carrier separation efficiently. However, the weak interfacial interaction can block electron transfer and complicate synthesis methods restrict the practical application of catalysts. Here, we report an interfacial enhanced amorphous porous NbO x (OH) y /g-C 3 N 4 heterostructure composite through a spontaneous coupling process. It was characterized by XRD, TEM, FT-IR, XPS, NH 3 -TPD and CO 2 -TPD, ect., which demonstrated that NbO x (OH) y possess amorphous porous structures with high specific surface area (205 m 2 /g) and plenty of acidic sites (418 μmol/g) as well as basic sites (184 μmol/g) contributed from uncoordinated Nb and -OH. These acidic and basic sites electrostatically attract -NH x and C-OH on the surface of g-C 3 N 4 to form hydrogen bonds (Nb-O-H⋅⋅⋅NH 2 , Nb-O⋅⋅⋅H-O-C), showing a strong electron interaction between NbO x (OH) y and g-C 3 N 4 . When tested as a photocatalyst for water splitting under visible light, the optimal NbO x (OH) y / CN-0.05 heterostructure composite exhibits a hydrogen evolution rate of 53 μmol/g/h, which is about 14 times higher than that of g-C 3 N 4 (3.8 μmol/g/h) and is even superior than P25 (16 μmol/g/h). These present findings lay a foundation for the synthesis of strongly interacting heterogeneous composites.

FeOx spatially confined in porous CeO2 induces an effective oxygen activation that improves CO preferential oxidation performance.