Electrocatalytic Nitrogen Reduction to Ammonia Using TiO₂-Supported Cu₄Cl₄(PPh₃)₄ and Ag₄Cl₄(PPh₃)₄ Nanoclusters

The electrocatalytic nitrogen reduction reaction (ENRR) offers a sustainable and promising approach for synthesizing ammonia under ambient conditions, providing an alternative to conventional industrial processes. However, challenges such as the inherent inertness of N 2 and the competing hydrogen evolution reaction (HER) in aqueous electrolytes hinder ammonia yield and Faradaic efficiencies. This research use TiO 2 -supported Cu 4 Cl 4 (PPh 3 ) 4 and Ag 4 Cl 4 (PPh 3 ) 4 nanoclusters (NCs) with quasi-cubic M 4 Cl 4 cores (M = Ag or Cu) for ENRR investigations. The results reveal that TiO 2 -supported Cu 4 Cl 4 (PPh 3 ) 4 NCs achieved an ammonia yield of 4.25 μg·h –1 ·cm –2 with a Faradaic efficiency (FE) of 53.0% at −0.9 V vs RHE. In contrast, TiO 2 -supported Ag 4 Cl 4 (PPh 3 ) 4 NCs produced a yield of 3.60 μg·h –1 ·cm –2 and an FE of 51.39% at −0.8 V vs RHE. Both NCs on the TiO 2 support demonstrated superior performance compared to their unsupported counterparts, underscoring the critical role of TiO 2 in improving electron transfer and fostering synergistic effects, thereby boosting catalytic activity. This research offers important insights into the design of supported NCs as high-performance catalysts, advancing the development of environmentally sustainable and energy-efficient approaches for ammonia production.