Fabrication of Cu nanoparticles@MOF composites via partial pyrolysis of hybrid dual-MOFs for high-efficiency electrocatalytic nitrate reduction

Abstract

Different MOFs with lattice coordination for thermal stability are combined to fabricate to hybrid "dual-MOFs", and are partially pyrolyzed under controlled annealing conditions to prepare Cu nanoparticles@MOF (Cu@C/ZIF-8) composites. Cu@C/ZIF-8 composites demonstrate the excellent electrocatalytic nitrate reduction performance (NH3 yield of 9374 µg h-1 mg-1cat.) with Faraday efficiency (FE) reaching up to 99.29%, which are better than those of Cu nanoparticles (NH3 yield of 5974 μg h⁻¹ mgcat.⁻¹ and FE of 97.85%) and ZIF-8 (NH3 yield of 513 μg h⁻¹ mgcat.⁻¹ and FE of 48.24%). In addition, the Cu@C/ZIF-8 composites exhibit excellent stability and outstanding electrochemical durability. The small Cu nanoparticles (NPs) encapsulated in Cu@C/ZIF-8, along with their uniform distribution and microenvironment, can be well controlled to improve electrocatalytic performance.