Rapid-heating-assisted metal–support interaction formation: Pd nanoparticles on boron nitride nanotubes as electrocatalysts for high N2-to-ammonia yields

Abstract

The electrochemical nitrogen (N₂) reduction reaction (eNRR) is pivotal for synthesizing green ammonia (NH₃) under ambient conditions. However, challenges such as mitigating the detrimental hydrogen evolution reaction (HER) and overcoming the sluggish proton-coupled electron transfer (PCET) step limit the efficiency of the eNRR process. Here, we present a metal–support heterostructure catalyst comprising uniform and high-density palladium nanoparticles (Pd NPs) on defective boron nitride nanotubes (D-BNNTs) via the rapid radiative Joule-heating method. Notably, the strong electronic metal–support interaction (EMSI) between the BNNT defects and Pd NPs creates an electron-deficient state in the Pd NPs, significantly reducing the PCET step and suppressing the HER. This unique configuration of the Pd NPs supported on the D-BNNT catalyst exhibits outstanding NH₃ selectivity, achieving 68.0% in neutral aqueous electrolytes and 58.9% in acidic media with a yield rate of 8.69 × 10⁻¹⁰ mol s⁻¹ cm⁻². This approach offers a strategic pathway for catalyst engineering in electrochemical reactions, presenting significant potential for practical applications.