Abstract: Methods and Pd/V2O5 devices for hydrogen detection are disclosed. An exemplary method of preparing an improved sensor for chemochromic detection of hydrogen gas over a wide response range exhibits stability during repeated coloring/bleaching cycles upon exposure and removal of hydrogen gas. The method may include providing a substrate. The method may also include depositing a V205 layer that functions as a H2 insertion host in a Pd/V205 hydrogen sensor to be formed on said substrate. The method may also include depositing a Pd layer onto said V205 layer; said Pd layer functioning as an optical modulator.