The Co₃O₄/g-C₃N₄ hybrids are constructed via the incipient wetness impregnation method by depositing Co₃O₄ onto the exterior of g-C₃N₄, and then employed for Hg⁰ capture within 60–240 °C. The results show that the Co₃O₄/g-C₃N₄ hybrid with a Co₃O₄ content of 12 wt% performs optimally with the highest Hg⁰ removal efficiency of ~100% at or above 120 °C. The high performances of the Co₃O₄/g-C₃N₄ hybrids are probably attributed to the tight interfacial contact between Co₃O₄ and g-C₃N₄, with its improved electron transfer, inferring that cobalt oxide and g-C₃N₄ display a cooperative effect towards Hg⁰ removal. NO and SO₂ shows a significant suppressive influence on the mercury capture performance, plausibly owing to the competing adsorption and side reactions.