(Invited) Design Strategies of PdCu Bimetals for Engineering Selectivity Toward Nitrogen and Ammonia from Electrochemical Nitrate Reduction

Abstract

Electrochemical conversion of harmful nitrate (NO3 -) has attracted attention to produce benign dinitrogen (N2) and ammonia (NH3) fuel. The designed construction of PdCu bimetallic nanoparticles is important for developing highly efficient and selective electrocatalysts. Here, we engineered the atomic structure of Pd/Cu and controlled Cu surface coverage on Pd nanocube nanoparticle to enhance the NO3 - conversion rate and steer the selectivity of N2/NH3. Highly ordered structure of PdCu nanoparticles showed high nitrate reduction activity and excellent dinitrogen selectivity in a neutral electrolyte compared to disordered PdCu nanoparticles. We also develop Pd nanocube nanoparticles and introduce Cu metals on the surface by underpotential deposition (UPD) method. The decorated Cu metals catalyze the reduction of NO3 - to NO2 - and the Pd (100) enhances the activity and selectivity of NO2 - to N2. Rotating disk electrode (RDE) and H-cell tests were conducted for NO3 -/NO2 - reduction activity and the selectivity of PdCu bimetal electrocatalysts were examined by UV-vis and in-situ mass spectrometry. This study demonstrates that design nanostructure of PdCu is an efficient approach to facilitate the nitrate reduction process and control the selectivity of N2/NH3.