Abstract This is a discussion of three articles by Tripodi et al. [P. Tripodi, M.C.H. McKubre, F.L. Tanzella, P.A. Honnor, D.Di Gioacchino, F. Celani, V. Violante, Phys. Lett. A 276 (2000) 122; P. Tripodi, D.Di. Gioacchino, R. Borelli, J.D. Vinko, Physica C 388–389 (2003) 571; P. Tripodi, D.Di. Gioacchino, J.D. Vinko, Physica C 408–410 (2004) 350] on the possibility of high temperature superconducting phases in PdH. The experimental results as well as their interpretations are discussed. Critical remarks concerning the definition of superconductivity and the possibility of preparation of PdH x (for x ≫ 1) by electrochemical method are presented.