Improving the electrocatalytic N2 reduction activity of Pd nanoparticles through surface modification

Abstract

Industrially, NH₃ production mainly relies on the energy-intensive Haber–Bosch process with the release of a large amount of CO₂. Electrochemical fixation of N₂ to NH₃ under ambient conditions is an environmentally friendly and sustainable alternative, but the N₂ reduction reaction (NRR) requires stable and efficient electrocatalysts. In this work, we report that the electrocatalytic NRR activity of Pd nanoparticles can be improved by surface modification with oxygen-rich tannic acid. The electrochemical test results in 0.1 M Na₂SO₄ suggest that such a catalyst achieves a large NH₃ yield of 24.12 μg h⁻¹ mg_cat.⁻¹ and a high faradaic efficiency of 9.49% at −0.45 V vs. the reversible hydrogen electrode (RHE), rivaling the performances of most of the reported aqueous-based NRR electrocatalysts. In addition, it also shows strong long-term electrochemical stability.