Lattice Hydrogen Involved Electrocatalytic Nitrate Reduction to Hydroxylamine

Area of Science:

• Electrochemistry
• Materials Science
• Sustainable Chemistry

Background:

• Electrocatalytic nitrate reduction to hydroxylamine (ENRH) is a sustainable synthesis route for NH₂OH.
• Current methods using active hydrogen (*H) face challenges with insufficient *H leading to nitrite accumulation or excessive *H causing ammonia overproduction.

Purpose of the Study:

• To address the limitations of active hydrogen sources in ENRH.
• To develop a novel electrocatalyst utilizing lattice hydrogen (H_lat) as a controlled hydrogen source.

Main Methods:

• Design and synthesis of a Cu-MnO₂H electrocatalyst.
• Investigation of Cu-triggered Jahn-Teller distortion in [MnO₆] octahedra to enhance H_lat.
• Electrocatalytic performance evaluation using isotopic tracking and theoretical calculations.

Main Results:

• The Cu-MnO₂H catalyst demonstrated high Faradaic efficiency (91.1%) and yield (396.6 mmol g_cat.^-1 h^-1) for NH₂OH.
• Lattice hydrogen (H_lat) was proven to enrich and buffer, providing a suitable hydrogen source for selective nitrate reduction.
• The catalyst outperformed most previously reported catalysts for ENRH.

Conclusions:

• Lattice hydrogen (H_lat) offers a promising alternative hydrogen source for selective electrocatalytic nitrate reduction to hydroxylamine.
• The Cu-MnO₂H electrocatalyst provides an effective platform for controlled ENRH.
• This approach enhances NH₂OH synthesis efficiency and selectivity under ambient conditions.