The invention provides a two-dimensional layered ternary nano-composite photocatalyst, and a preparation method and application thereof. The preparation method comprises the following steps: placing
melamine in a
muffle furnace, and calcining to obtain g-C3N4;
grinding the g-C3N4 into
powder, adding the
powder into deionized water, and performing
ultrasonic dispersion to obtain a g-C3N4 suspension; and adding
nickel nitrate hexahydrate and
cobalt nitrate hexahydrate into the g-C3N4 suspension, stirring for a first time, dropwise adding
ammonia water, transferring into a high-pressure kettle, carrying out a
hydrothermal reaction, and carrying out post-treatment to obtain the two-dimensional layered ternary nano-composite photocatalyst. A water reduction cocatalyst and a water oxidation cocatalyst are introduced at the same time, under the synergistic effect of the water reduction cocatalyst and the water oxidation cocatalyst,
electron-hole separation is accelerated, and the
catalytic efficiency is improved; and the material with a two-dimensional
layered structure is compounded, so that the interface contact area is increased, the transfer of interface charges is accelerated, and the photocatalytic activity is effectively improved.