Regenerable Cu9S5/NC Catalyst for Electrochemical Ammonia Synthesis
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Solution Overview
Problem
Current methods for ammonia synthesis, such as the Haber-Bosch process, are energy-intensive and environmentally detrimental, while alternative electrochemical nitrogen reduction reactions (eNRR) face challenges of low Faradaic efficiency and ammonia production yield due to the need for high-energy nitrogen bond breaking.
Innovation Solution
A copper-sulfur compound (Cu9S5) integrated with N-doped carbon (NC) is used as a catalyst for electrochemical ammonia synthesis, prepared through a thermal heating process and solid-state reaction. This catalyst is regenerated electrochemically using Na2S to maintain activity in continuous eNRR reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If electrochemical nitrogen reduction reaction is used to produce ammonia from N2 and H2O under ambient conditions, then environment-friendly and renewable ammonia production is achieved, but low Faradaic efficiency and ammonia production yield occur due to the high energy required to break the strong triple bond of N2
Solution Approach 1:
The patent modifies the catalyst's electronic structure by integrating nitrogen-doped carbon with copper sulfide, changing the electronic parameters to optimize nitrogen adsorption and activation. This parameter change enables efficient breaking of the N2 triple bond under ambient conditions, resolving the contradiction between environmental benefits and production yield.
Solution Approach 2:
The patent uses a composite catalyst structure combining copper sulfide with nitrogen-doped carbon materials. This composite approach leverages the synergistic effects of both materials: copper sulfide provides catalytic activity for nitrogen reduction, while nitrogen-doped carbon enhances electron transfer and stabilizes the catalyst structure, thereby improving ammonia production yield while maintaining environmental benefits.
2Productivity
If conventional Haber-Bosch process is used for ammonia production, then high ammonia production yield is achieved, but high energy consumption and severe environmental problems such as large quantity of CO2 emission occur
Solution Approach 1:
The patent replaces the mechanical/thermal system of Haber-Bosch process (high temperature and pressure) with an electrochemical system that operates under ambient conditions. By using electrical energy to drive the nitrogen reduction reaction through a specialized catalyst, the process achieves ammonia production without the high energy consumption and CO2 emissions associated with conventional thermal methods.
Solution Approach 2:
The patent fundamentally changes the operating parameters from high temperature and pressure to ambient conditions, utilizing electrochemical energy instead of thermal energy. This parameter transformation enables ammonia production with significantly lower energy consumption while maintaining high productivity through optimized catalytic activity.
3Reliability
If various eNRR catalysts are investigated to improve eNRR performance, then catalyst activity is enhanced, but catalyst regeneration capability is lacking
Solution Approach 1:
The patent designs a catalyst system that possesses inherent regeneration capability through its composite structure. The nitrogen-doped carbon component facilitates the restoration of active sites on the copper sulfide surface after reaction, enabling the catalyst to self-regenerate and maintain high activity over multiple cycles without external intervention or complex regeneration procedures.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The Cu9S5/NC catalyst achieves superior ammonia synthesis activity compared to single metal or metal oxide catalysts, with a Faradaic efficiency of 35% and ammonia production yield of 645 nmol/hcm2 at -0.5 VRHE, while the regeneration process extends catalyst durability and maintains high production yields.
Implementation Method 1
electrochemical nitrogen reduction reaction (eNRR) has been proposed as an alternative method for producing NH3 from N2 and H2O under ambient conditions
Implementation Method 2
prepared through a thermal heating process and solid-state reaction
Implementation Method 3
the regeneration process extends catalyst durability and maintains high production yields
Data Source
AI summary
The present disclosure relates to a catalyst for electrochemical synthesis of ammonia, which includes a metal sulfide, a method for preparing the same and a method for regenerating the same.