Laser-Assisted Synthesis of Pd Aerogel with Compressive Strain for Boosting Formate and Ethanol Electrooxidation

Owing to the increasing energy demands, direct small-molecule fuel cells, such as ethanol and formate fuel cells, have attracted great attention. During the operation of the fuel cell, noble metal catalysts are widely used to accelerate the reaction kinetics by alloying with other materials. However, there are a few facile methods for improving elemental metal catalytic activity. In this work, the defect-rich palladium (Pd) aerogels are acquired by laser ablating technology, which can significantly improve the intrinsic activity of Pd elementary catalysts through introducing defects and lattice strain. The electrochemical results show that the mass and specific activities of the obtained Pd aerogel for the formate oxidation reaction are 2.26 and 1.99 times higher than those of the commercial Pd/C. The excellent activity and stability of the Pd aerogel for ethanol oxidation reaction have also been demonstrated. The effect of the compressive strain is further investigated by density functional theory (DFT) calculations. It has been found that the compressive strain weakens the adsorption strength of the intermediates, which can facilitate the desorption of toxic specifics. The laser-assisted synthesis of defect-rich aerogel paves a way in optimizing the structure of the elemental metal catalysts and improving their intrinsic catalytic activity.