Efficient electrocatalytic urea synthesis from CO2 and nitrate over the scale-up produced FeNi alloy-decorated nanoporous carbon

Abstract

Electrocatalytic urea synthesis provides a favorable strategy for conventional energy-consuming urea synthesis, but achieving large-scale catalyst synthesis with high catalytic efficiency remains challenging. Herein, we developed a simple method for the preparation of a series of FeNi-alloy-based catalysts, named FeNi@nC-T (n represents the content of nanoporous carbon as 1, 3, 5, 7 or 9 g and T = 900, 950, 1000 or 1100 °C), for highly performed urea synthesis via NO₃⁻ and CO₂ co-reduction. The FeNi@7C-1000 achieved a high urea yield of 1041.33 mmol h⁻¹ g_FeNi⁻¹ with a Faradaic efficiency of 15.56% at –1.2 V vs. RHE. Moreover, the scale-up synthesized FeNi@7C-950-S (over 140 g per batch) was achieved with its high catalytic performance and high stability maintained. Mechanism investigation illuminated that the Ni and Fe sites catalyze and stabilize the key *CO and *N intermediates and minimize the C–N coupling reaction barriers for highly efficient urea synthesis.