MOF-Derived Hollow C, N-Doped Co<sub>3</sub>O<sub>4</sub> Dodecahedral Nanostructure Enwrapped with MgIn<sub>2</sub>S<sub>4</sub> Nanosheets for Enhanced Photocatalytic N<sub>2</sub> Reduction
Ranjit Bariki, Sudhir K. Sahoo, Aditya Ranjan Pati, Sibun Kumar Pradhan, Saumyaranjan Panda, Swagat Kumar Nayak, Braja Gopal Mishra
Abstract
Design of hierarchical hollow nanoheterostructure materials through interfacial and defect engineering is an innovative approach for achieving optimal charge separation dynamics and photon harvesting efficiency. Herein, we have described a facile technique to fabricate hollow MOF-derived C, N-doped-Co 3 O 4 (C, N-Co 3 O 4 ) dodecahedral particles enwrapped with MgIn 2 S 4 nanosheets for enhanced N 2 reduction performance. ZIF-67 was initially used as a sacrificial template to prepare hollow C, N-Co 3 O 4 using a carbonization route followed by low-temperature calcination treatment. The controlled synthetic protocol not only led to nonmetal doping but also produced an interwoven carbon matrix that improved the photoelectron mobility. Density functional theory calculations further substantiated the creation of atomic defects through substitution of C at tetrahedral Co 2+ sites and N at lattice O 2– sites of the Co 3 O 4 structure. C, N-Co 3 O 4 was subsequently coupled with MgIn 2 S 4 nanosheets to prepare the C, N-Co 3 O 4 /MgIn 2 S 4 [C, N-CM ( X )] p–n heterojunctions. The photocatalytic study revealed that the NH 4 + ion production activity of the optimal C, N-CM (1:1) material (334 μmol g –1 h –1 ) was significantly higher (4–10 times) than that of pure components. The enhanced activity of the composite was ascribed to its distinct topological features, superior charge carrier dynamics, and creation of atomic defects that afforded a large number of surface-active sites.