Glyphosate is a widely used herbicide in agriculture. Its residues pose a great threat to ecological balance and human health. The potential impact of glyphosate and its by-products on the soil and water environment is of great concern. Here, a core-shell structured cobalt-nickel bimetallic sulfide NiCo₂S₄/Co₉S₈/NiS (NCS) is synthesized by a simple two-step hydrothermal method, and used as a novel peroxymonosulfate (PMS) activator for degradation of glyphosate. The effects of various reaction conditions on the degradation of glyphosate in the NCS-PMS system are investigated. The NCS is used to activate PMS by the dual redox cycle of Co²⁺/Co³⁺ and Ni²⁺/Ni³⁺ under its core-shell structure to efficiently degrade glyphosate. The optimized NCS achieved 82.2% removal of 10^-4 mol⋅L^-1 glyphosate in 35 min with an initial pH=3.9. The removal performance is 25.7 and 1.5 times higher than that of monometallic sulfides Ni₃S₂/NiS and Co₃S₄ prepared by the same process of NCS, respectively. The radical quenching experiments reveal that NCS interacted with PMS to generate SO₄^•− and •OH radicals, O₂^·- as well as ¹O₂ together to achieve efficient degradation of glyphosate. The main intermediates of glyphosate degradation by NCS-activated PMS are identified by liquid chromatography-quadrupole time-of-flight mass spectrometry, and possible degradation pathways of glyphosate are proposed and the relative toxicity of degraded products is evaluated. This work provides a novel insight to produce high-performance multiphase catalysts for glyphosate degradation as well as practical applications.

草甘膦是一种广泛用于农业的除草剂。其残留物对生态平衡和人类健康构成巨大威胁。草甘膦及其副产品对土壤和水环境的潜在影响备受关注。在这里，通过简单的两步水热法合成了核壳结构的钴镍双金属硫化物 NiCo ₂ S ₄ /Co ₉ S ₈ /NiS (NCS)，并将其用作新型过氧单硫酸盐 (PMS) 活化剂用于降解草甘膦。研究了不同反应条件对NCS-PMS系统中草甘膦降解的影响。NCS用于通过Co ²⁺ /Co ³⁺和Ni ²⁺ /Ni的双重氧化还原循环激活PMS³⁺在其核壳结构下有效降解草甘膦。优化后的 NCS 在 35 分钟内实现了 82.2% 的 10 ^-4 mol·L ^-1草甘膦去除率，初始 pH=3.9。去除性能分别是NCS相同工艺制备的单金属硫化物Ni ₃ S ₂ /NiS和Co ₃ S ₄的25.7倍和1.5倍。自由基猝灭实验表明NCS与PMS相互作用产生SO ₄ ^•-和•OH自由基、O ₂ ^·-以及¹ O ₂共同实现草甘膦的高效降解。采用液相色谱-四极杆飞行时间质谱鉴定了NCS活化PMS降解草甘膦的主要中间体，提出了草甘膦可能的降解途径，并评价了降解产物的相对毒性。这项工作为生产用于草甘膦降解的高性能多相催化剂以及实际应用提供了新的见解。