Pb²⁺和Cu²⁺等重金属是地下水中持久性污染物之一。对这些金属进行频繁监测需要高效、灵敏、经济、可靠的方法。文中提出了一种基于纳米复合材料的微型电极，利用方波伏安电化学分析技术同时检测Pb²⁺和Cu²⁺。文中还提出一种简便的原位水热煅烧法，无需黏合剂即可直接在三维泡沫镍上生长介孔氧化镍，然后用电化学方法在泡沫镍中嵌入金纳米颗粒（AuNP）。介孔氧化镍和AuNP之间低势垒欧姆接触的精心设计，有助于介孔氧化镍内靶标介导的纳米通道限域电子转移。因此，该方法可以同时准确测定重金属Pb²⁺（检测限为0.020 mg·L⁻¹，检测范围为2.0~16.0 mg·L⁻¹）和Cu²⁺（检测限为0.013 mg·L⁻¹，检测范围为0.4~12.8 mg·L⁻¹）。此外，地下水中的其他重金属离子和常见干扰离子对电极性能的影响微乎其微，地下水样品加标回收率在96.3% ± 2.1%和109.4% ± 0.6%之间。此电极结构紧凑、形状灵活、功耗低，而且可以远程操作，这为现场检测地下水中的重金属开辟了新的技术路径，进而展示了在环境监测领域进行革新的潜力。

Heavy metals, notably Pb²⁺ and Cu²⁺, are some of the most persistent contaminants found in groundwater. Frequent monitoring of these metals, which relies on efficient, sensitive, cost-effective, and reliable methods, is a necessity. We present a nanocomposite-based miniaturized electrode for the concurrent measurement of Pb²⁺ and Cu²⁺ by exploiting the electroanalytical technique of square wave voltammetry. We also propose a facile in situ hydrothermal calcination method to directly grow binder-free mesoporous NiO on a three-dimensional nickel foam, which is then electrochemically seeded with gold nanoparticles (AuNPs). The meticulous design of a low-barrier Ohmic contact between mesoporous NiO and AuNPs facilitates target-mediated nanochannel-confined electron transfer within mesoporous NiO. As a result, the heavy metals Pb²⁺ (0.020 mg·L⁻¹ detection limit; 2.0-16.0 mg·L⁻¹ detection range) and Cu²⁺ (0.013 mg·L⁻¹ detection limit; 0.4-12.8 mg·L⁻¹ detection range) can be detected simultaneously with high precision. Furthermore, other heavy metal ions and common interfering ions found in groundwater showed negligible impacts on the electrode’s performance, and the recovery rate of groundwater samples varied between 96.3% ± 2.1% and 109.4% ± 0.6%. The compactness, flexible shape, low power consumption, and ability to remotely operate our electrode pave the way for onsite detection of heavy metals in groundwater, thereby demonstrating the potential to revolutionize the field of environmental monitoring.