This study demonstrates a green and facile strategy to develop electrochemical sensors through the rational design of platinum nanoparticles@polyoxometalate decorating ordered mesoporous carbon (Pt@POMs-OMC) nanohybrids. The Keggin-type POMs, H₃PW₁₂O₄₀, was applied to serve as a both reducing and stabilizing agent. The as-prepared nanohybrids were characterized comprehensively by X-ray diffraction, X-ray photo-electron spectroscopy, energy-dispersive X-ray spectroscopy, and transmission electron microscopy. The novel nanohybrids of Pt@POMs-OMC can provide new features for electro-catalytic applications because of the synergetic effects of Pt nanoparticles and OMC materials. This study reports on the use of Pt@POMs-OMC as an effective sensing template for enhanced hydrazine, hydrogen peroxide (H₂O₂), and nitrobenzene (NB) electrochemical detection for the first time. It exhibits a steady amperometric response towards hydrazine in the linear concentration range of 10–840 μM with a sensitivity of 2.92 μA mM⁻¹ and from 840 to 1400 μM with a sensitivity of 7.32 μA mM⁻¹; the limit of detection was calculated to be 3.41 μM. It shows a steady amperometric response towards H₂O₂ in the linear concentration range of 5–5400 μM with a sensitivity of 10.64 μA mM⁻¹ and a limit of detection of 1.09 μM. The NB sensor displays a linear range of 3.98–672.55 μM with a sensitivity of 102.62 μA mM⁻¹ and a limit of detection of 3.82 μM. The successful fabrication of Pt@POMs-OMC holds great promise for the design of electrochemical sensors and is a promising material to promote the development of new electrode materials.