Electrochemically synthesized SnO₂ with tunable oxygen vacancies for efficient electrocatalytic nitrogen fixation

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• Electrochemical nitrogen reduction reaction (NRR) is a sustainable method for ammonia synthesis.
• Efficient catalysts are crucial for overcoming the high reaction barrier and improving selectivity.
• Defect engineering is a key strategy for optimizing catalyst surface properties.

Purpose of the Study:

• To synthesize tin dioxide (SnO2) with varying oxygen vacancy concentrations using a controllable electrochemical method.
• To investigate the effect of oxygen vacancies on the electrocatalytic performance of SnO2 for nitrogen fixation.
• To understand the mechanism by which oxygen vacancies enhance the NRR.

Main Methods:

• Controlled electrochemical synthesis of SnO2 with tunable oxygen vacancy concentrations.
• Electrocatalytic performance evaluation for NRR, including ammonia yield rate and Faradaic efficiency.
• Density functional theory (DFT) calculations to elucidate the reaction mechanism.

Main Results:

• The synthesized SnO2 catalysts exhibited excellent NRR performance.
• An optimal NH3 yield rate of 25.27 μg h-1 mgcat.-1 and 11.48% Faradaic efficiency were achieved at -0.6 V.
• NRR performance improved with increasing oxygen vacancy concentration.

Conclusions:

• Oxygen vacancies in SnO2 enhance NRR by providing more active sites and improving electron transfer.
• Defect engineering of SnO2 is a promising strategy for efficient electrocatalytic ammonia synthesis.
• DFT calculations confirmed that oxygen vacancies facilitate N2 adsorption and activation, lowering the reaction barrier.