Modulating Catalyst Surface Wettability to Boost Electrochemical Ammonia Synthesis under Ambient Conditions

Abstract

The electrochemical nitrogen reduction reaction (NRR) offers a sustainable alternative to the energy-intensive Haber-Bosch process by enabling ammonia synthesis under ambient conditions. However, the practical application of NRR remains limited by low selectivity and Faradaic efficiency, largely due to the competing hydrogen evolution reaction (HER), which is kinetically and thermodynamically favored. Recent research has highlighted the potential of interfacial surface engineering, especially the integration of hydrophobic and hydrophilic domains, to modulate the gas-liquid-solid environment and enhance NRR activity. This review focuses on how hydrophilic-hydrophobic heterostructures can be strategically designed to improve NRR selectivity and efficiency. Drawing insights from carbon dioxide reduction reaction (CO 2 RR) and other gas-phase electrocatalytic systems, we discuss how wettability modulation facilitates nitrogen adsorption, suppresses HER, and improves charge and mass transfer at the catalyst interface. While wettability-based strategies are well established in CO 2 RR, their application to NRR remains significantly underexplored, presenting an opportunity for targeted catalyst development. We examine recent progress in material synthesis, surface modification, and wettability tuning to extract key design principles and identify future research directions for next-generation NRR catalysts. The insights offered aim to bridge critical knowledge gaps and accelerate the development of efficient, scalable platforms for sustainable ammonia production.