Bimetallic-enhanced hierarchical flower-like SnO₂ enables low-temperature hydrogen sensing for potential breath hydrogen detection

The development of high-performance hydrogen sensors operating at low-temperature is imperative for the large-scale application of green hydrogen energy and for the diagnosis of gastrointestinal diseases through the detection of H₂ biomarkers in exhaled breath. However, conventional metal oxide semiconductor gas sensors often suffer from insufficient response and sluggish kinetics under low-temperature operating conditions. In this work, bimetallic-enhanced hierarchical flower-like SnO₂ was synthesized via solvothermal and impregnation. Through systematic comparison among different bimetallic systems, the PdPt/SnO₂ sensor demonstrated optimal performance, exhibiting a response of 26.78 toward 250 ppm H₂ at 80°C, along with rapid response/recovery kinetics (5 s/125 s). Furthermore, theoretical calculations were performed to study the impact of Au/Ag/Pd/Pt on the adsorption characteristics and electronic behavior of oxygen and hydrogen on the SnO₂ surface. Hydrogen breath tests demonstrated the ability of the sensor to detect exhaled hydrogen, thereby highlighting its potential for diagnosing lactose intolerance and small intestinal bacterial overgrowth.