To improve the selectivity and sensitivity for naked-eye detection of toxic Hg²⁺, water-soluble Ag₂S nanoparticle stabilized by graphene oxide (Ag₂S@GO) was identified by virtue of the high catalytic activity of nano Ag₂S and the excellent physicochemical property of graphene oxide. After its structure and spectral performance were characterized and investigated, it was noted that the proposed Ag₂S@GO possesses outstanding Hg²⁺-activated oxidase-like activity to oxidize the chromogenic substrate of 3,3′,5,5′,-tramethylbenzidine (TMB) with an obvious hyperchromic effect from colorless to blue in the presence of Hg²⁺ exclusively. Under the optimized conditions, the Ag₂S@GO+TMB system was successfully applied for naked-eye detection of heavy metal Hg²⁺ in real environmental samples, with a nmol·L⁻¹-level detection limit of 9.8 × 10^–9 mol/L, an accurate recovery among 97.0–101.8% and a low standard deviation less than 3.3%. The Hg²⁺-activated oxidase-like activity of Ag₂S@GO and its exclusive recognition mechanism to toxic Hg²⁺ were also proposed.

为提高肉眼检测有毒Hg ²⁺的选择性和灵敏度，利用纳米Ag ₂ S和Hg ²⁺的高催化活性，鉴定了由氧化石墨烯（Ag ₂ S @ GO）稳定的水溶性Ag ₂ S纳米颗粒。氧化石墨烯的优异物理化学性能。在对其结构和光谱性能进行表征和研究后，注意到所提出的Ag ₂ S @ GO具有出色的Hg ²⁺激活的氧化酶样活性，可氧化3,3'，5,5'，-的生色底物在存在Hg ²⁺的情况下，苯甲基乙基联苯胺（TMB）具有从无色到蓝色的明显增色作用只。在最佳条件下，Ag ₂ S @ GO + TMB系统成功应用于肉眼检测真实环境样品中的重金属Hg 2 ⁺，nmol·L ^-1级检测限为9.8×10 ^–9 mol / L，准确回收率在97.0–101.8％之间，低标准偏差小于3.3％。还提出了Ag ₂ S @ GO的Hg ²⁺激活类氧化酶活性及其对有毒Hg ^2+的唯一识别机制。