Ni-MOF-74 derived nickel phosphide and In2O3 form S-scheme heterojunction for efficient hydrogen evolution

Abstract

S-scheme heterojunction is a new photocatalytic hydrogen production system, which can effectively eliminate useless electron–hole pairs and improve the efficiency of photocatalytic hydrogen production. In this work, Ni-MOF-P(Ni₂P)/In₂O₃ composite photocatalyst was prepared with Ni-MOF-74 and In₂O₃ by a one-step calcination-phosphating method. The prepared composite catalyst maintained a specific parallelogram-layered structure of Ni-MOF-74 and constructed S-scheme heterojunction. Various characterization techniques such as XRD, SEM, and XPS were used for the characterization of the photocatalyst, which proved that the Ni-MOF-P/In₂O₃ composite photocatalyst was successfully synthesized for the photocatalytic performance. SEM study showed that In₂O₃ was excellently compounded on Ni₂P, and the cycling experiments and XRD of the sample after the cycling experiment proved their outstanding stability. The amount of hydrogen evolution with a mass ratio of Ni₂P and In₂O₃ of 1 : 0.3 was 494.17 μmol (within 5 h), which is 3 times the hydrogen evolution of Ni-MOF-P. In this work, a novel and simple method for preparing non-noble metal phosphides was proposed for photocatalytic hydrogen evolution using a photocatalyst.