Plasmon-enhanced hot electron enrichment in Cu@MoS2 heterostructure boosts the electrocatalytic nitrate reduction

Cu@MoS 2 simultaneously enables NO 3 adsorption and *H supply. • Cu@MoS 2 -2 exhibits excellent structural stability and consistent catalytic performance. • Under light irradiation, Cu@MoS 2 -2 generates abundant high-energy hot electrons. • Cu@MoS 2 -2 achieves 94% FE and 0.526 mmol h −1 cm −2 NH 3 yield at − 0.5 V vs. RHE. Electrochemical nitrate (NO 3 − ) reduction (NO 3 RR) to ammonia (NH 3 ) is a sustainable strategy for converting nitrate-contaminated wastewater into valuable resources. However, the process involves a complex proton-coupled electron transfer (PCET) that requires eight electrons and nine protons. Herein, the localized surface plasmon resonance (LSPR) arising from Cu nanoparticles anchored on MoS 2 nanosheet arrays (Cu@MoS 2 ) is harnessed to regulate electron dynamics and enhance active hydrogen (*H) availability for NO 3 RR. Under simulated sun irradiation, the optimized Cu@MoS 2 heterostructure delivers a stable NH 3 evolution rate of 0.526 mmol h −1 cm −2 with a Faradaic efficiency (FE) of 94.0% at − 0.5 V, which is about 7.2 and 12 times higher than bare MoS 2 (0.073 mmol h −1 cm −2 ) and Cu (0.0438 mmol h −1 cm −2 ), respectively. This work demonstrates the capability of plasmonic cocatalysts to convert supplementary photon flux into multiple catalytic driving forces, opening a new avenue toward boosting catalytic activity through direct utilization of free solar energy. Download: Download high-res image (205KB) Download: Download full-size image