An Ambient-Robust Differential Gasochromic Hydrogen Sensor with a Collect–Concentrate–Detect Mechanism for Early-Stage Leak Detection

Early detection of hydrogen (H2) leaks is critical for H2 safety. However, conventional fixed-point H2 sensors often fail to detect trace leaks promptly because of rapid H2 gas dispersion and limited monitoring coverage. Herein, we present an ambient-robust differential gasochromic H2 sensor based on a Pd/WO3 film for early-stage leak detection. The sensor employs a differential measurement strategy, providing strong immunity to environmental fluctuations in temperature, humidity, and ambient light, maintaining remarkable signal stability throughout a rigorous 28 h continuous outdoor field test at a 1 Hz sampling rate. An integrated H2 collect–concentrate–detect mechanism efficiently captures trace amounts of leaked H2 and extends the effective detection radius. On this basis, we further demonstrate a H2 leak detection system with a 2 × 2 gasochromic sensor array capable of delivering reliable early warnings and comprehensive monitoring coverage, significantly outperforming conventional sensor networks. Our work offers a transformative and practical strategy for substantially enhancing early-warning performance in next-generation H2 detection platforms.