In-MOF derived In2S3-X@ZnS heterojunction with rich sulfur vacancies for enhanced performance in photocatalytic nitrogen fixation

Photocatalytic nitrogen fixation has the characteristics of green, energy-saving and environment-friendly. Herein, the hollow microtube-flower In2S3-X@ZnS with rich sulfur vacancies was synthesized by the one-step solvothermal method of sulfurization from the precursor MIL-68(In). In-MOF derived sulfur-vacancy modulation and the construction of the In2S3-X@ZnS heterojunction had been proved to be the desirable strategies to dramatically enhance the ammonia production rate. One the one hand, the characterizations of HRTEM, ESR and the transient photocurrent responses (TPR) in N2, Air and Ar saturated solution directly and indirectly proved the existence of rich sulfur-vacancy, which could be the active sites for the chemisorption and activation of N2. On the other hand, the results of EIS, PL and band analysis demonstrated that the established Type-п heterojunction promoted the photogenerated carriers to separate and clarified the enhanced photocatalytic mechanism, the corresponding nitrogen fixation performance had been greatly improved with a high yield rate of 58.988 µmol∙gcat−1∙h−1, which was evidently much higher than that of pristine In2S3-X and pure ZnS. This work provided a new insight for developing functional photocatalysts with the synergy effect of sulfur-vacancy and heterojunction for highly efficient nitrogen fixation.