A series of Pd/TiO 2 /SiO 2 /Si multilayers were produced using magnetron sputtering method. It is found that H 2 molecules have dramatic effect on the current–voltage ( I–V ) characteristics of the Pd/TiO 2 /SiO 2 /Si multilayers at room temperature (RT). When Pd/TiO 2 /SiO 2 /Si multilayer is exposed to H 2 , the Pd film quickly reacts with H 2 and forms palladium hydride which results in transferring more electrons from the Pd film to TiO 2 film. Therefore, the I–V characteristic of Pd/TiO 2 /SiO 2 /Si multilayer was greatly changed when exposed to H 2 . For example, a Pd/TiO 2 /SiO 2 / p -Si multilayer can show a high response (∼2431%) to 1% H 2 with appreciable short response time of 13 s and recovery time of 4 s at RT. Besides, it is demonstrated that Si substrate has a great effect on the H 2 response of Pd/TiO 2 /SiO 2 /Si multilayers. When exposed to H 2 the current of Pd/TiO 2 /SiO 2 / p -Si multilayer at −0.5 V greatly decreases while the current of Pd/TiO 2 /SiO 2 / n -Si multilayer greatly increase, which can be understood by their energy band structures. [ABSTRACT FROM AUTHOR]