Concentration‐Adaptive Electrocatalytic Urea Synthesis From CO ₂ and Nitrate via Porphyrin and Metalloporphyrin MOFs

Traditional urea synthesis via the Bosch–Meiser process suffers from high energy consumption and greenhouse gas emissions. Electrocatalytic urea production from carbon dioxide (CO 2 ) and nitrate (NO 3 − ) under ambient conditions offers a sustainable alternative, yet challenges persist due to variable NO 3 − concentrations and competing side reactions. Herein, we propose porphyrin metal‐organic framework (PMOF) and Cu‐porphyrin MOF (Cu‐PMOF) catalysts for NO 3 − concentration‐adaptive urea synthesis. Density functional theory (DFT) calculations reveal that PMOF weakly adsorbs *NO 2 via hydrogen bonding, favoring its coupling with *CO 2 , while Cu‐PMOF strongly binds *NO 2 at Cu sites, facilitating spontaneous *NO/*CO coupling to form *OCNO intermediates under dilute NO 3 − conditions. Experimentally, PMOF achieves a urea yield of 28.6 µmol h −1 mg cat −1 and a Faradaic efficiency (FE) of 23.1% in 0.1 M NO 3 − , whereas Cu‐PMOF outperforms in 0.05 M NO 3 − with a yield of 25.5 µmol h −1 mg cat −1 and FE of 52.7%. In situ spectroscopy and mechanistic study confirm distinct pathways: PMOF relies on stepwise coupling of *HNO 2 with *CO 2 , while Cu‐PMOF enables consecutive *NO‐*CO coupling. This work highlights adaptive electrocatalyst design for efficient C‐N coupling, advancing sustainable urea synthesis.