Fluorine-free 2D MBene for dual ultra-sensitive and anti-interference ethylene sensor in plants

Abstract

Pursuing plant-wearable ethylene sensors combining extreme sensitivity and environmental robustness faces fundamental material challenges in interfacial design and sustainable fabrication. We present a fluorine-free hydrothermal etching strategy that synthesizes Mo_1.33B₂T_x MBenes through HCl concentration-controlled crystallization (10–12 mol/L). The 11 mol/L-optimized MBene (B₁₁) features a compact lamellar architecture with 0.38 nm interlayer spacing and oxygen-rich terminals (XPS: 68.3 at.%), enabling quantum-confined charge transfer (DFT: 0.98 e⁻) and record ethylene adsorption energy (−3.803 eV) via p-π* orbital hybridization. This atomic-level interface engineering yields a wearable biosensor with dual breakthrough performance: 0.01 ppm detection limit (lowest reported) with 30s response and < 8.92 × 10³ % resistance drift over 1000 bending cycles. A biomimetic encapsulation system combining electromagnetic shielding (42 dB SNR enhancement) and superhydrophobic PDMS suppresses 97.3 % environmental interference while maintaining epidermal conformability (Young's modulus: 2.4 MPa). Field deployments across postharvest species (kiwifruit ΔR/R₀ = 1.21; banana = 0.89; tomato = 1.57) demonstrate multispecies tracking accuracy (R² = 0.986 vs. GC–MS) with 92 % humidity immunity. Our work establishes three transformative advances: (1) the first eco-friendly MBene synthesis protocol, (2) a materials-by-design paradigm linking termination chemistry to sensing specificity, and (3) a modular sensor architecture bridging lab-scale innovation to agricultural IoT scalability.