The invention discloses a monometal
selenide catalyst rich in
selenium vacancy and having a heterostructure, and a preparation method and application thereof, and belongs to the field of catalysts. The preparation method comprises the following steps: S1, dissolving a single
metal M salt and
urea in deionized water to form a
mixed solution A; then carrying out primary
hydrothermal reaction to obtain a
metal precursor; s2, NaBH4 and Se
powder are dissolved in deionized water, and a clear solution B is obtained; then adding a
metal precursor into the solution B, wherein the
molar ratio of the element M in the metal precursor to the element Se in the
selenium powder is (0.5-1.8): 1; and after
ultrasonic dispersion, carrying out secondary
hydrothermal reaction at 160-220 DEG C to obtain the product. According to the invention, controllable synthesis of nanosheets, nanotubes, nanoparticles and the like with different morphologies can be realized by regulating and controlling the structure of the precursor. Based on the regulation and
control effect of heterogeneous interface
engineering on the catalytic activity of an interface
electronic structure and an
active site, the catalyst shows excellent activity and selectivity in a double-
electron oxygen reduction reaction, and the H2O2 selectivity can reach 97%.