Enhanced colorimetric detection of hydrogen using PdO-decorated ZnO covered with a metal-organic framework membrane

Safety concerns dictate the need for an affordable method of detecting the leakage of hydrogen. Simple colorimetric hydrogen sensors may provide a solution for achieving such detection. Herein, we report significant enhancements in eye-readable hydrogen detection via the formation of a metal-organic framework membrane on the surface of a hydrogen-responsive pigment. As a model system, PdO-decorated ZnO covered with a zeolitic imidazolate framework-8 (PdO/ZnO@ZIF-8) is synthesized and verified through material characterizations. When compared to a bare PdO/ZnO sensor, a colorimetric hydrogen sensor fabricated from PdO/ZnO@ZIF-8 yields a remarkably shortened response time, a moderate increase in detection sensitivity, and a significant enhancement in selectivity against potential interferents. These improvements are interpreted with the molecular sieving effect, electronic modulation of active centers, and accelerated sorption kinetics of hydrogen. The outstanding pigment is utilized to prepare a hydrogen detection tape that demonstrates a great potential in naked-eye detection of a hydrogen leak. • Eye-readable detection of hydrogen using the PdO/ZnO pigment coated with zeolitic imidazolate framework-8. • The microporous framework results in an excellent selectivity to H 2 and a greatly shortened response time. • Fabrication and verification of a colorimetric tape for hydrogen detection.