# Spin‐Selective Anti‐Perovskite Enables Breakthrough Nitrate‐to‐Ammonia Electrocatalysis

## TL;DR

A new antiperovskite catalyst enables efficient conversion of nitrate to ammonia through spin-selective interactions, offering environmental and energy benefits.

## Contribution

The study introduces a CuNCo3 antiperovskite catalyst that stabilizes spin-selective Co sites, enabling high-performance nitrate-to-ammonia electrocatalysis.

## Key findings

- CuNCo3 achieves 100% Faradaic efficiency and a high NH3 production rate of 124.6 mg mgcat⁻¹ h⁻¹ at -0.4 V vs. RHE.
- Spin-selective Co sites lower hydrogenation barriers and accelerate key steps in nitrate reduction.
- Operando techniques reveal Cu's role in promoting partial Co-N cleavage and charge redistribution, enhancing catalytic efficiency.

## Abstract

Electrochemical nitrate reduction to ammonia offers environmental and energy benefits, but progress is hindered by sluggish multistep proton‐coupled electron transfers and competing side reactions. Here, we introduce an antiperovskite CuNCo3 catalyst featuring a 3d–3d interaction framework. This framework stabilizes spin‐selective Co sites even upon surface Co‐N bond cleavage and drives asymmetric nitrate consumption. CuNCo3 achieves 100% Faradaic efficiency and an NH3 production rate of 124.6 mg mgcat
−1 h−1 at −0.4 V vs. RHE. Operando XAS, XES, and ATR‐FTIR directly link the evolution of spin‐selective Co sites with specific NO3RR intermediates, revealing that spin‐selective Co sites lower hydrogenation barriers and accelerate key steps. These results demonstrate that spin‐selective anti‐perovskite frameworks provide a robust, earth‐abundant platform for high‐performance nitrate‐to‐ammonia electrocatalysts.

CuNCo3 antiperovskite leverages built‐in 3d–3d interactions to stabilize and generate spin‐selective Co sites during nitrate reduction. Multiple operando techniques reveal that Cu acts as a promoter, inducing partial surface Co‐N cleavage and Cu‐Co charge redistribution. This dynamic restructuring tunes the activation and conversion of nitrate‐derived intermediates, boosting overall catalytic efficiency and selectivity for ammonia formation.