A highly selective, efficient hydrogen gas sensor based on bimetallic (Pd-Au) alloy nanoparticle (NP)-decorated SnO2 nanorods

The surging worldwide demand for hydrogen highlights the crucial need for advanced detection technologies, essential for enhancing safety and optimizing utilization across various applications. In this context, we have constructed a highly sensitive hydrogen gas sensor based on SnO2 nanorods decorated with bimetallic (Pd-Au) alloy nanoparticles (NPs) (Pd-Au@SnO2). The material synthesis (Pd-Au@SnO2) was achieved through a hybrid approach involving a hydrothermal treatment and an in situ ascorbic acid reduction process. Various compositions of SnO2 nanorods were prepared by tailoring the bimetallic content of Pd and Au, which was accomplished by adding different volume ratios of their respective precursor solutions. Among the various synthesized combinations, the composition of SnO2 (S1-0.5) with bimetallic decoration (Pd-Au) in a volume ratio of 1 : 0.5 demonstrates superior gas sensing capabilities towards hydrogen (25-500 ppm) within the temperature range 100-200 degrees C. The S1-0.5 sensor shows a response (R-a/R-g) of 46.4 towards 100 ppm of hydrogen at 175 degrees C, which is 42.7 fold higher than the bare SnO2 (S0-0) and 2.7 fold higher than Pd decorated SnO2 (S1-0). The excellent gas sensing performance of the S1-0.5 sensor is due to the strong catalytic effect and the synergetic effect of both Pd and Au. The response and recovery times of the S1-0.5 sensor were measured to be 19 s and 302 s, respectively. Furthermore, the S1-0.5 sensor also showed a high selectivity toward gaseous NH3, CO2, CO, and ethanol with a high stability and repeatability.

Automated summary

The increasing demand for hydrogen worldwide emphasizes the importance of advanced detection technologies. A highly sensitive hydrogen gas sensor based on SnO2 nanorods decorated with bimetallic (Pd-Au) alloy nanoparticles has been constructed and shows excellent gas sensing capabilities and high selectivity.