Lattice Nitrogen Couples Cuδ+ Stabilization With Pathway Control for CO2-to-Methanol Electroreduction.

Abstract

Dynamic catalyst reconstruction is an unavoidable feature of Cu-catalyzed CO2 electroreduction, yet for methanol synthesis it creates a fundamental stability-selectivity conflict: the cathodic potentials required for CO2 reduction simultaneously destroy the partially oxidized Cu sites needed to retain oxygenated intermediates. Here, we show that lattice-incorporated nitrogen resolves this conflict by regulating both catalyst evolution and reaction-pathway selection in amorphous CuO. Nitrogen creates a resilient Cu-N/O coordination environment that suppresses excessive Cu reduction and preserves catalytically relevant Cuδ+ sites. The optimized N/a-CuO catalyst achieves a methanol Faradaic efficiency of 48% in an H-type cell and a methanol partial current density of 42.8 mA cm-2 in a flow cell, corresponding to 266.3 µmol h-1 cm-2. Operando spectroscopy reveals enhanced accumulation of bridge-bound *CO and its subsequent conversion to oxygenated intermediates. Density functional theory further shows that nitrogen-induced charge redistribution stabilizes Cuδ+ sites and selectively lowers the free energy of the pathway-diverging *CHOH intermediate through a favorable C-N interaction, promoting C─O bond retention and methanol formation over methane. These findings establish lattice nitrogen as a strategy for coupling dynamic active-site stabilization with intermediate-specific pathway control in multielectron electrocatalysis.

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