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 mgcat.-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.