Positive direction of polarization-induced electric field improves formic acid electrooxidation on Pd

Adjusting the adsorption energy of adsorbates on catalyst can directly regulate the catalytic performance and reaction pathways of heterogeneous catalysis. Herein, we report a novel strategy, introducing polarization-induced electric field (PIEF) with different directions, to manipulate the adsorption energy of intermediates and reaction pathway of formic acid electrooxidation on Pd. Tourmaline nanoparticles are applied as the PIEF provider, of which the direction is successfully controlled via aligning the dipoles in tourmaline in a strong external electric field. Experimental and theoretical results systematically reveal that positive PIEF leads to an electron-deficient state of Pd, reduced adsorption energy of CO_ad, enhanced adsorption energy of *HCOOH and *OH, and promoted formate pathway of formic acid electrooxidation. Pd/TNP+/FTO, with the aid of positive PIEF, shows three-fold enhancement in the formic acid electrooxidation (4.74 mA·cm⁻²) with high durability and anti-poisoning ability compared with pristine Pd. This study leads a new route to design formic acid electrocatalysts and provides an understanding on how to control the adsorption energy of adsorbates on electrocatalysts by an internal electric field.