Microplasma-induced vapor generation (μPIVG), particularly using only hydrogen, has attracted increasing attention in the field of atomic spectrometry. However, its application for field analysis of environmental samples remains limited owing to the difficulty of hydrogen storage and transportation. Herein, a non-noble metal electrode-based hydrogen evolution reaction (HER) was utilized as a safe and environment-friendly hydrogen supply method for the efficient μPIVG of Hg, Cd and Zn. Subsequently, HER-μPIVG was used for the sensitive field detection of Hg, Cd and Zn in environmental samples via miniature point discharge optical emission spectrometry (μPD-OES). In contrast to conventional hydrogen-enhanced μPIVG, hydrogen was produced in situ and in real time using a superior cathode composed of cobalt-phosphorous nanomaterial, eliminating the storage and transport of hydrogen requirements and improving the safety, sensitivity, and feasibility of μPIVG-μPD-OES. Under the optimized conditions, the limits of detection (LODs) were 0.8, 10, and 14 μg L?1 for Hg, Cd, and Zn, respectively, with relative standard deviations (RSDs) of < 4.7%. The accuracy and practicability of the proposed method were validated through Hg, Cd, and Zn determinations in two certified reference materials (CRMs) and several water samples with satisfactory results.