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WO₃ loaded with noble metals is well-known to be sensitive to reducing gases and can be used as hydrogen sensor. This paper presents a simple and attractive method concerning the preparation of hydrogen sensors based on Pd-loaded WO₃ nanocomposites with different morphologies. The influences of the morphology of WO₃ and the palladium growth on its surface on the hydrogen sensing performances are studied. WO₃ nanospheres, nanowires and nanolamellae were synthesized by different methods starting from the same precursor (H₂WO₄·nH₂O) which has been obtained by acidification of sodium tungstate (Na₂WO₄). The prepared WO₃ nanostructures were modified with the Pd by dispersing them in a PdCl₂ containing solvent using sonication (giving Pd-WO₃ inks). The sensors were prepared by screen-printing thick films (∼10 μm) of these inks on alumina substrates fitted with gold electrodes. The …