The emission of mercury from anthropogenic activities is a serious concern in both developed and developingcountries due to its high toxicity and persistence. Here, carbon nitride nanosheets (CNNS) were attained via atwo-step thermal etching method and applied for Hg0 removal. Proper deposition of ZnS can markedly reinforce the Hg0capture ability of CNNS. 10ZnS/CNNS notably outperforms ZnS and CNNS at 100 oC, which is primarily attributed tosurface chemisorbed oxygen species and polysulfide active sites. Besides, Hg0 adsorption and thermal catalytic oxidationpathways are further disclosed using quantum chemistry calculations based on density functional theory (DFT). The calculation results show that the presence of zinc species is beneficial to the decomposition of adsorbed oxygen,which plays a key role in the catalytic oxidation of Hg0, thereby contributing to the enhancement of mercury removalperformance.