One-step photochemical deposition of PdAu alloyed nanoparticles on TiO2 nanowires for ultra-sensitive H-2 detection

TiO2 nanostructures are widely used for H-2 detection in scientific and technological research fields, but how to detect ppm-level H-2 in a timely and sensitive manner at room temperature remains challenging. In this work, TiO2 nanowires were synthesized on a Ti foil substrate via the hydrothermal method, and then decorated with PdAu alloyed nanoparticles (NPs) via a one-step photochemical deposition method. What's more, the Pd/Au atomic ratio in alloyed NPs could be adjusted by just changing the Pd2+/Au3+ ratio in the precursor solution. H-2 sensing experiments indicate that sensitization with Pd or PdAu alloyed NPs makes TiO2 nanowire films highly sensitive to ppm-level H-2 at room temperature. The role of Au in alloyed NPs is estimated by comparing the sensing performance of PdAu@TiO2 with different Pd/Au ratios in alloyed NPs and references (e.g., TiO2, Au@TiO2 and Pd@TiO2). The results indicate that the as-synthesized PdAu@TiO2 with less than 25% Au in alloyed NPs exhibits higher sensitivity and a faster response than Pd@TiO2, and plausible enhancement mechanisms of the Au component in alloyed NPs on the performance of PdAu@TiO2 are also supplied.