Related Experiment Video
Updated: Aug 12, 2026

Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O
Published on: October 7, 2020
Relay Cascade Catalysis on Ru-Co Dual Sites Enables Selective Nitrate-to-Ammonia Conversion in Wastewater
Mengxue Yang1, Wenzhe Wang1, Zhiyong Zhao1
1MOE Key Laboratory of Pollution Processes and Environmental Criteria/Tianjin Key Laboratory of Environmental Remediation and Pollution Control, College of Environmental Science and Engineering, Nankai University, Tianjin300350, P. R. China.
Abstract:
Electrocatalytic nitrate (NO3-) reduction reaction (NO3RR) enables simultaneous nitrate removal and ammonia (NH3) recovery from wastewater, yet kinetic mismatch among sequential hydrogenation steps limits NH3 selectivity. Here, we report an atomic-scale relay cascade catalyst composed of adjacent Ru-Co dual sites anchored on a CeOx support (Co3Ru4-CeOx) that spatially coordinates these elementary steps. Ru sites promote nitrate adsorption and deoxygenation, while neighboring Co sites accelerate nitrite hydrogenation, as supported by in situ spectroscopy and theoretical calculations. This establishes a kinetically favorable regime (R2 > R1), where downstream conversion outpaces intermediate formation, thereby suppressing nitrite accumulation and enabling selective NH3 synthesis with a Faradaic efficiency (FE) of 97.1%. Integrated into an electrocatalytic membrane reactor, the catalyst mitigates mass-transfer limitations via convective transport and sustains high selectivity in low-concentration nitrate wastewater (1-10 mM). Techno-economic analysis indicates an estimated production cost of $2.08 per kg NH3, highlighting a scalable approach for coupling wastewater treatment with nitrogen recovery.
More Related Videos
08:40Synthesis of Metal Nanoparticles Supported on Carbon Nanotube with Doped Co and N Atoms and its Catalytic Applications in Hydrogen Production
Published on: December 6, 2021
10:39Heterogeneous Removal of Water-Soluble Ruthenium Olefin Metathesis Catalyst from Aqueous Media Via Host-Guest Interaction
Published on: August 23, 2018
Related Concept Videos
Catalysis
Catalysis
Inorganic Nitrogen Assimilation
Heterogeneous Catalysis
Rate-Determining Steps
In a multistep reaction mechanism, one of the elementary steps progresses significantly slower than the others. This slowest step is called the rate-limiting step (or rate-determining step). A reaction cannot proceed faster than its slowest step, and hence, the rate-determining step limits the overall reaction rate.
The concept of rate-determining step can be understood from the analogy of a 4-lane freeway with a short-stretch of traffic-bottleneck caused due to...
Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...