Ru/CeO2 Ammonia Catalyst with Controlled Mesopore Structure
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Solution Overview
Problem
Conventional Ru catalysts supported on CeO2 and Ru-supported La2Ce2O7 do not exhibit sufficiently high ammonia synthesis activity.
Innovation Solution
An ammonia synthesis catalyst is developed with a specific peak pore diameter and pore volume range, achieved by heat-treating a cerium oxide-based catalyst support precursor under reducing conditions, incorporating ruthenium and optionally additional metal oxides, to enhance ammonia synthesis activity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional Ru catalysts are supported on CeO2 with typical pore structures, then the catalyst can be prepared using standard synthesis methods, but the ammonia synthesis activity is insufficient
Solution Approach 1:
The patent applies parameter changes by precisely controlling the pore structure parameters of the CeO2 support, specifically setting the pore volume in the 10-16 nm range to 0.10 cm3/g or more and in the 8-20 nm range to 0.16 cm3/g or more. This controlled adjustment of pore parameters significantly enhances ammonia synthesis activity compared to conventional catalysts with typical pore structures.
Solution Approach 2:
The patent uses a composite material system consisting of Ru metal particles supported on CeO2 ceramic support with controlled pore structure. This composite structure combines the catalytic activity of Ru with the high surface area and tunable pore architecture of CeO2, achieving superior ammonia synthesis performance that neither component could achieve alone.
2Productivity
If the pore volume of the catalyst support is increased to enhance mass transport, then the accessibility of active sites improves, but the structural stability of the support may be compromised
Solution Approach 1:
The patent applies local quality by creating a hierarchical pore structure with different pore size distributions in specific ranges. The support has optimized pore volumes in the 10-16 nm and 8-20 nm ranges while maintaining overall structural integrity. This localized optimization of pore characteristics in specific size ranges enhances mass transport without compromising the global structural stability of the CeO2 support.
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 catalyst exhibits excellent ammonia synthesis activity, enabling efficient synthesis of ammonia from hydrogen and nitrogen.
Implementation Method 1
subjecting a catalyst support precursor including cerium oxide having a specific peak pore diameter and a specific pore volume to heat treatment in a reducing atmosphere under specific temperature conditions
Implementation Method 2
heat treatment in a reducing atmosphere
Implementation Method 3
ruthenium supported on the catalyst support
Implementation Method 4
ammonia synthesis catalyst comprising a catalyst support including cerium oxide and ruthenium supported on the catalyst support
Data Source
AI summary
An ammonia synthesis catalyst including a catalyst support including cerium oxide and ruthenium supported on the catalyst support, wherein a peak pore diameter is in a range of 8 to 16 nm, and a pore volume in a pore diameter range of 10 to 16 nm is 0.10 cm3/g or more, and/or a pore volume in a pore diameter range of 8 to 20 nm is 0.16 cm3/g or more, as measured by a Barrett-Joyner-Halenda (BJH) method.