Engineering Palladium Surfaces to Enhance the Electrochemical Storage of Hydrogen

Materials can be engineered to have enhanced hydrogen storage capabilities during electrolysis by modifying the composition of the first few atomic layers. The changes in composition of the near surface can radically affect the electrochemical insertion of hydrogen. The hydrogen stored under galvanostatic conditions was investigated after altering the composition of the Pd surface with various combinations of Pb, Bi, and Pt. It was found that the addition of a underpotential deposition of Bi on the Pd cathode increases the hydrogen content from PdH0.77 to PdH0.81 at −10.9 mA cm−2, and the addition of Pt to the Bi further increased the hydrogen content to PdH0.87. This work provides a fundamental basis for the future design of surface alloys yielding enhanced electrochemical hydrogen storage in Pd and other hydrogen absorbing materials.