Lewis acid-triggered hydroxyl spillover enables selective urea electrooxidation to nitrite with concurrent energy-saving hydrogen production

Nitrite (NO2⁻) is a high-value chemical pivotal to agriculture and pharmaceuticals, yet its conventional via the Ostwald process is energy-intensive and polluting. Electrochemical urea oxidation reaction (UOR) offers a sustainable NO2⁻ synthesis pathway with concurrent energy-saving hydrogen (H2) production, but suffers from non-selective N2/CO2 pathways. Here, we report Cr3+ Lewis acid sites in Ni3S2 that act as hydroxyl (OH⁻) pumps, dynamically spilling OH⁻ to adjacent Ni sites via a Lewis acid-base interaction. This triggers a urea-to-NO2⁻ pathway, achieving a NO2⁻ yield of 120.98 mg h-1 cm-2 (600 mA cm-2). The OH⁻ spillover accelerates C-N cleavage while suppressing N-N coupling, enabling energy-saving H2…

• NN
  National Natural Science Foundation of China

  Award: 22162020
• FO
  Foundation of Henan Educational Committee

  Award: 2023GGJS091