Laser‐Regulated CoFeRu‐LDH Nanostructures: Nitrite‐to‐Ammonia Production in Zn–Nitrite Battery and Oxygen Evolution in Water Electrolysis
Sieon Jung, Raja Arumugam Senthil, Cheol Joo Moon, Anuj Kumar, Mohd Ubaidullah, Myong Yong Choi
Abstract
Abstract Herein, the design and synthesis of Ru‐doped CoFe‐layered double hydroxide (CoFeRu─LDH) nanostructures is presented via an innovative yet straightforward pulsed laser method. The CoFeRu─LDH catalyst demonstrates outstanding electrocatalytic performance, achieving a high NH 4 + Faradaic efficiency (FE) of 89.65% at −0.7 V versus reversible hydrogen electrode for nitrite reduction reaction (NO 2 − RR) and a low overpotential of 297 mV at 10 mA cm −2 for oxygen evolution reaction (OER). Comprehensive in situ and ex situ analyses reveal the electrochemically energetic species formed on the CoFeRu─LDH surface during the NO 2 − RR and OER. Theoretical studies confirm that Ru doping plays an imperative role in tuning the electronic structure of CoFeRu─LDH, lowering its reaction barriers, and thereby remarkably enhancing its NO 2 − RR and OER performance. Specifically, a galvanic Zn–nitrite battery using CoFeRu─LDH as the cathode efficiently converts NO 2 − to NH 4 + with an FE of 96.8% while concurrently generating electricity with a power density of 4.14 mV cm −2 . Furthermore, pairing CoFeRu─LDH as the anode with Pt/C as the cathode in water electrolysis enables H 2 production at a low cell voltage of 1.57 V at 10 mA cm −2 . This study presents a new pathway to designing versatile, high‐performance electrocatalysts for sustainable energy conversion and the production of carbon‐free NH 3 and H 2 fuels.