Cataluminescence Sensor Based on ZnO–CuO Composites for Rapid and Selective Detection of Hydrogen Sulfide

Hydrogen sulfide (H 2 S) is a highly toxic and corrosive gas, necessitating rapid and selective detection strategies for environmental and occupational safety. In this work, a ZnO–CuO composites were rationally designed and synthesized via a hydrothermal route and evaluated as a cataluminescence (CTL) sensing material for H 2 S monitoring. The sensor demonstrated a strong CTL response under mild operating conditions, offering a detection limit as low as 4 ppm, rapid response, and recovery within 2.5 s, and excellent selectivity against a broad panel of volatile organic and inorganic gases. Mechanistic investigations were conducted using BET surface analysis and energy band modeling based on the p–n heterojunction structure to explore the origin of signal enhancement in the ZnO–CuO composites. Validation with simulated gas mixtures confirmed good recovery and practical feasibility. These findings demonstrate the significant potential of ZnO–CuO composites for selective, sensitive, and rapid H 2 S monitoring in the workplace.