High Turnover Frequency in the Electrocatalytic Reduction of Nitrous Oxide to Dinitrogen at a Binuclear Copper Complex of 3,5‐Diamino‐1,2,4‐Triazole

Abstract

Abstract Nitrous oxide (N 2 O) is a potent greenhouse gas and an ozone‐depleting substance. Electrocatalytic N 2 O reduction (e‐N 2 ORR) is a promising approach to remove N 2 O from the air under ambient conditions. However, developing noble‐metal‐free e‐N 2 ORR electrocatalysts with high Faradaic efficiency (FE) and turnover frequency (TOF) remains a challenge because of the weak binding of N 2 O and the high kinetic barrier for deoxygenation reaction. In this work, inspired by the multinuclear copper active site of nitrous oxide reductases, a binuclear copper complex of 3,5‐diamino‐1,2,4‐triazole supported on carbon black of Ketjenblack (CuHdatrz/KB) was utilized for the e‐N 2 ORR at pH 13 and 298 K. CuHdatrz/KB achieves a high FE of ≈ 100% at −0.3 V versus reversible hydrogen electrode for the e‐N 2 ORR to N 2 and TOF up to ≈ 700 h −1 , which is one–two orders of magnitude higher than those of the previously reported molecular‐based catalysts. In situ X‐ray absorption spectroscopy confirmed that Cu(II) ions of CuHdatrz/KB are reduced to Cu(I) keeping the binuclear core, suggesting that the multinuclear copper active site is crucial to efficiently catalyze the e‐N 2 ORR like the nitrous oxide reductase.