Ru-Doped Pd Nanoparticles for Nitrogen Electrooxidation to Nitrate

Electrocatalytic nitrogen oxidation to nitrate is a promising alternative to the conventional nitrate synthesis industry, which is accompanied by huge energy consumption and greenhouse gas emission. However, breaking the N equivalent to N triple bond (941 kJ center dot mol-(1)) in nitrogen is still challenging, and thus, the development of efficient electrocatalysts with established reaction pathways is highly required. Herein, a series of Ru-doped Pd materials are prepared, and the optimized Pd0.9Ru0.1 sample exhibits superior performance for electrocatalytic nitrogen oxidation into nitrate, greatly outperforming pure Pd and Ru samples. The N-15 isotope-labeling studies and other characterizations results indicate that the produced nitrate originates from N-2 electrooxidation. Electrochemical in situ Raman spectra reveal the formed Pd0.9Ru0.1O2 on the surface serves as the active species. Electrochemical in situ Fourier transform infrared spectroscopy and online differential electrochemical mass spectrometry experimentally unveil the reaction pathway of nitrogen electrooxidation on Pd0.9Ru0.1O2.. The combined results of experiments and theoretical simulations reveal Ru doping not only promotes the formation of more active species but also changes the potential-limiting step with a lower energy barrier.

Automated summary

In this study, Ru-doped Pd materials were prepared for electrocatalytic nitrogen oxidation, with the optimized Pd0.9Ru0.1 sample showing superior performance over pure Pd and Ru. Experimental and theoretical simulations indicate that Ru doping promotes the formation of more active species and changes the potential-limiting step with a lower energy barrier.