Pd based nanoporous metals with superior catalytic activity

Abstract

This work reports the effects of metallic glass compositions on the compositions and catalytic activities of the dealloyed Pd based nanoporous metals (NPMs). The Pd10Ni70P20 and Pd10Ni50Co20P16B4 metallic glasses were potentiostatically dealloyed in an acid solution. The pore size of the as obtained NPMs is similar and <100 nm. The NPM dealloyed from Pd10Ni70P20 contains ∼89 at-% Pd, 8 at-% Ni and 3 at-% P. The NPM dealloyed from Pd10Ni50Co20P16B4 has 85 at-% Pd, 11 at-% Ni, 3 at-% Co and 1 at-% P. Both of the NPMs exhibit lower formic acid electro-oxidation potential when compared with the commercial Pd/C catalyst. It should be noticed that the NPM dealloyed from Pd10Ni50Co20P16B4 shows dramatically enhanced catalytic activity toward formic acid electro-oxidation, as is evidenced from the low formic acid electro-oxidation potential at 350 mV (versus RHE), which may contribute to the existence of proper amount of Ni and Co residuals in the NPM. The simultaneous addition of Ni and Co can remarkably increase the occupation of the lower unoccupied molecular orbital of the Pd clusters and thus improve the catalytic activity.