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In this study, we explore the efficacy of gold (Au) as a selective electrocatalyst for the reduction of nitrate to hydroxylamine, a valuable nitrogen-based chemical, while also evaluating the by-product formation of ammonia. We systematically optimized various experimental parameters including nitrate concentration, pH, and applied potential. We found that at an applied potential of −0.7 V vs. RHE in 0.1 M HNO3, Au achieves a 230.1 ± 19 μmol NH2OH h−1 cm−2 yield, with a 34.2 ± 2.8% faradaic efficiency. This study underscores the potential of Au as an efficient and selective electrocatalyst for generating value-added nitrogen products through an electrochemical pathway. [ABSTRACT FROM AUTHOR]

The validity of N2 reduction experiments relies on control experiments with isotopically labeled 15N2. Here we discovered significant 15NH3 contamination (73 ppm) in commercial 15N2 and also observed the prescence of oxidized 15N in amounts comparable to the typical reported ammonia yields. [ABSTRACT FROM AUTHOR]

The d-band center of a catalyst can be applied for the prediction of its catalytic activity, but the application of d-band theory for the electrocatalytic nitrogen reduction reaction (eNRR) has rarely been studied in perovskite materials. In this work, a series of double-perovskite LaCo x Ni 1- x O 3 (LCNO) nanorods (NRs) were synthesized as models, where the d-band centers can be modulated by changing the stoichiometric ratios between Co and Ni elements. Experimentally, the LCNO-III NRs ( x = 0.5) attained the highest faradic efficiency and NH 3 yield rate among various LCNO NRs. This result matches well with the finding from theoretical calculations that LCNO-III has the most positive d-band center (ε d = -0.96 eV vs Fermi level), thus confirming that LCNO-III shows the strongest adsorption ability for N 2 molecules (adsorption energy value of -2.01 eV) for the subsequent N 2 activation and reduction reactions. Therefore, this work proposes a general rule to adopt for developing novel catalysts (especially perovskite-based catalysts) for substantially increasing the eNRR activity by modulating the corresponding d-band centers.