Construction of Co3O4 nanopolyhedra with rich oxygen vacancies from ZIF-67 for efficient photocatalytic nitrogen fixation

Abstract

Photocatalytic nitrogen fixation has attracted much attention due to the fact that it is a way of using solar energy to achieve clean and sustainable conversion of nitrogen to ammonia under mild conditions. In this paper, different proportions of Zn-doped Co 3 O 4 nanopolyhedrons were synthesized using bimetallic ZIFs containing Co 2+ and Zn 2+ as precursors for the construction of photocatalytic nitrogen fixation semiconductor materials for the first time. The synthesized Co 3 O 4 nanopolyhedron still retains the rhombic dodecahedron shape of ZIF-67 and exhibits a large specific surface area. Moreover, Zn doping results in abundant oxygen vacancies on the surface of Co 3 O 4 polyhedron. These oxygen vacancies not only provide active sites for nitrogen adsorption and activation, but also enhance the separation ability of photocarriers, which can significantly improve the efficiency of photocatalytic nitrogen fixation of the material. When Zn-Co 3 O 4 -30 is utilized as the catalyst for photocatalytic nitrogen fixation, the nitrogen fixation rate is 96.8 μmol g −1 h −1 , which is much higher than that of pure-Co 3 O 4 . In this study, heteroatom-doped Co 3 O 4 polyhedron with rich oxygen vacancy was synthesized by low-temperature oxidation method, which provides a new idea for the design and synthesis of skeleton-based photocatalytic nitrogen fixation materials.

Limitation of WO3 in Zn-Co3O4 Nanopolyhedra by the Pyrolysis of H3PW12O40@BMZIF: Synergistic Effect of Heterostructure and Oxygen Vacancies for Enhanced Nitrogen Fixation

“…Herein, we considered combining POMs and ZIFs into composite nanomaterials due to their fully complementary sizes and excellent properties . In the previous work, we successfully synthesized polyhedrons Zn-Co 3 O 4 with abundant oxygen vacancies . Also, based on that, we have synthesized Zn-doped Co 3 O 4 nanopolyhedron loaded with WO 3 nanoparticles from BMZIF and H 3 PW 12 O 40 (PW 12 ) as precursors through calcination.…”

“…31 In the previous work, we successfully synthesized polyhedrons Zn-Co 3 O 4 with abundant oxygen vacancies. 32 Also, based on that, we have synthesized Zn-doped Co 3 O 4 nanopolyhedron loaded with WO 3 nanoparticles from BMZIF and H 3 PW 12 O 40 (PW 12 ) as precursors through calcination. The synergistic action of Zn atom doping and WO 3 nanoparticles resulted in the composite containing more oxygen vacancies, which offered useful locations for the adsorption of N 2 .…”