SnS Catalyst Interlayer Spacing for Ammonia Synthesis
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Solution Overview
Problem
The electrochemical nitrate reduction reaction (eNO3RR) for ammonia synthesis faces challenges due to low NH3 selectivity and Faradaic efficiency, primarily because of complex by-products and competitive hydrogen evolution reactions, especially in large-scale applications, where 2D materials exhibit unsatisfactory catalytic performance.
Innovation Solution
A catalyst comprising a first and second layer of metal monochalcogenide-based material, such as SnS, with interlayer spacing adjusted by doping with a lanthanide atom like Ce and intercalating with a transition metal atom like Pt, enhancing the chemical affinity and catalytic activity for ammonia synthesis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If 2D material is used for eNO3RR, then large specific area is provided for catalytic reactions, but NH3 selectivity and Faradaic efficiency remain unsatisfactory
Solution Approach 1:
The patent applies parameter changes by precisely controlling the interlayer spacing of 2D metal monochalcogenide materials through doping with lanthanide atoms (e.g., Ce) and intercalation with metal atoms (e.g., Pt). This structural parameter adjustment optimizes the chemical affinity of adsorbates on active sites, thereby improving NH3 selectivity and Faradaic efficiency while maintaining the large specific area advantage of 2D materials
Solution Approach 2:
The patent employs composite materials by creating doped and intercalated 2D metal monochalcogenide structures (e.g., CexPty-MX). The combination of host 2D material with dopant atoms and intercalated metal atoms produces synergistic effects that enhance catalytic performance for eNO3RR, achieving both high NH3 selectivity and maintained surface area
2Manufacturing precision
If interlayer spacing of 2D material is adjusted to improve catalytic performance, then chemical affinity of adsorbates is affected, but structural transformation and constant external stimulation are required
Solution Approach 1:
The patent applies preliminary action by incorporating dopant atoms (e.g., Ce) and intercalated metal atoms (e.g., Pt) into the 2D material structure during synthesis. This preliminary structural modification establishes the desired interlayer spacing and catalytic properties in advance, eliminating the need for constant external stimulation or structural transformation during operation to maintain optimal performance
3Productivity
If eNO3RR is performed at large scale, then ammonia production increases, but NH3 selectivity and Faradaic efficiency decrease due to complex by-products and competitive HER
Solution Approach 1:
The patent applies parameter changes by optimizing the interlayer spacing parameter of the catalyst structure through doping and intercalation. This structural parameter optimization creates favorable conditions for the eight-electron transfer process in eNO3RR, suppressing competitive HER and minimizing by-product formation, thereby maintaining high NH3 selectivity and Faradaic efficiency even at large-scale production
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 adjusted interlayer spacing improves the Faradaic efficiency of ammonia synthesis to 94.12% and yield rate to 0.3056 mmol cm−2 h−1, significantly enhancing the catalytic performance and selectivity in electrochemical ammonia synthesis.
Implementation Method 1
The metal monochalcogenide-based material is doped by a lanthanide atom
Implementation Method 2
the second distance is an expansion of the first distance by about 4% to about 12%
Implementation Method 3
the first and second layers of metal monochalcogenide-based material are intercalated by a metal intercalating atom
Implementation Method 4
the third distance is a compression of the second distance by about 4% to about 12%
Implementation Method 5
the electrochemical nitrate reduction reaction (eNO3RR), which involves conversion of nitrate into ammonia
Implementation Method 6
the complex by-products in the eight-electron transfer process
Implementation Method 7
it may affect the chemical affinity of adsorbates on the active sites of the catalyst
Data Source
AI summary
A catalyst in ammonia synthesis includes a first layer of metal monochalcogenide-based material; a second layer of metal monochalcogenide-based material stacked with and is spaced from the first layer of metal monochalcogenide-based material by a first distance; wherein the metal monochalcogenide-based material includes SnS. A method of preparing the catalyst and an electrochemical ammonia synthesizing device making use of the catalyst thereof are also addressed.