Free radicals promote electrocatalytic nitrogen oxidation. Issue 7 (26th January 2023) - Wang, Zuochao
Abstract : In this work, we introduce hydroxyl radicals into the electrocatalytic nitrogen oxidation reaction (NOR) for the first time. Co3 O4 + ˙OH shows an excellent NOR performance among Co3 O4 catalysts in 0.1 M Na2 SO4 solution. Abstract : In this work, we introduce hydroxyl radicals into the electrocatalytic nitrogen oxidation reaction (NOR) for the first time. Cobalt tetroxide (Co3 O4 ) acts not only as an electrocatalyst, but also as a nanozyme (in combination with hydrogen peroxide producing ˙OH), and can be used as a high-efficiency nitrogen oxidation reaction (NOR) electrocatalyst for environmental nitrate synthesis. Co3 O4 + ˙OH shows an excellent nitrogen oxidation reaction (NOR) performance among Co3 O4 catalysts in 0.1 M Na2 SO4 solution. At an applied potential of 1.7 V vs. RHE, the HNO3 yield of Co3 O4 + ˙OH reaches 89.35 μg h −1 mgcat −1, which is up to 7 times higher than that of Co3 O4 (12.8 μg h −1 mgcat −1 ) and the corresponding FE is 20.4%. The TOF of Co3 O4 + ˙OH at 1.7 V vs. RHE reaches 0.58 h −1, which is higher than that of Co3 O4 (0.083 h −1 ), demonstrating that free radicals greatly enhance the intrinsic activity. Density functional theory (DFT) demonstrates that ˙OH not only can drive nitrogen adsorption, but also can decrease the energy barrier (rate-determining step) of N2 to N2 OH*, thus producing great NOR activity.