Atomically Dispersed Catalysts for Low-Temperature Biogas Upgrading
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Solution Overview
Problem
Conventional biogas-to-RNG technologies face challenges such as high temperature requirements, susceptibility to impurities, and the need for CO2 separation, limiting methane purity and catalyst efficiency.
Innovation Solution
Development of atomically dispersed transition metal catalysts, such as Ni, Ru, Rh, and Mo, dispersed on substrates like TiO2 or CeO2, which enable low-temperature biogas conversion to high-purity methane, reducing catalyst costs and eliminating the need for CO2 separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional Ni/Al2O3 catalysts are used for biogas methanation, then catalyst activity is achieved, but high temperature requirements and susceptibility to oxidation occur
Solution Approach 1:
The patent changes the fundamental parameter of catalyst structure from conventional nanoparticulate Ni/Al2O3 to atomically dispersed Ni sites on redox-active substrates (TiO2, CeO2). This structural parameter change enables the catalyst to operate at lower temperatures (250-400°C) while maintaining stability by preventing Ni oxidation through strong metal-support interactions and the redox properties of the substrate.
Solution Approach 2:
The patent creates a composite catalyst system combining atomically dispersed transition metal sites with redox-active metal oxide substrates (TiO2, CeO2). This composite structure provides synergistic effects where the metal sites catalyze methanation while the redox-active substrate prevents metal oxidation and enhances low-temperature activity through hydrogen spillover mechanisms.
2Manufacturing precision
If conventional catalysts are used, then biogas conversion occurs, but CO2 separation is required to achieve pipeline quality RNG
Solution Approach 1:
The patent changes the selectivity parameter of the catalyst to achieve near-complete conversion of CO2 to CH4 at low temperatures, producing pipeline-quality RNG (≥90% methane) directly without requiring downstream CO2 separation units, thus simplifying the overall process while maintaining high product purity.
3Productivity
If conventional catalyst formulations are used, then catalytic activity is achieved, but high catalyst costs result from inefficient metal utilization
Solution Approach 1:
The patent segments the catalyst into atomically dispersed individual metal sites rather than using conventional nanoparticulate structures. This segmentation maximizes the utilization of each metal atom, with every atom being catalytically active, thereby achieving high productivity at low metal loadings (0.1-5 wt%) and significantly reducing catalyst costs.
4Productivity
If conventional catalysts are used, then biogas conversion occurs, but impurities in biogas reduce catalyst efficiency and performance
Solution Approach 1:
The patent changes the catalyst's chemical environment parameter by dispersing metal atoms on redox-active substrates that can buffer against impurity effects. The metal-support interactions and redox properties of TiO2 or CeO2 create a more robust catalytic site that maintains high conversion efficiency even in the presence of typical biogas impurities.
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 described catalysts achieve a 10× improvement in low-temperature methanation rates and produce pipeline-quality RNG with reduced catalyst costs and complexity, overcoming thermodynamic and impurity-related barriers.
Implementation Method 1
atomically dispersed transition metal catalysts, such as Ni, Ru, Rh, and Mo, dispersed on substrates like TiO2 or CeO2, which enable low-temperature biogas conversion to high-purity methane
Implementation Method 2
the promotion hydrogen spillover, coupled with decreased diffusion distances, to maintain the desired oxidation state and preserve catalyst activity
Implementation Method 3
The substrate may be a redox active substrate, for example, TiO2 or CeO2
Data Source
AI summary
Described herein are catalysts and methods for converting waste biogas (e.g., a mixture of carbon dioxide and methane) into useful products. In some embodiments, the biogas is converted into a highly purified methane, that can be further processed to generate fuel products, including recycled natural gas (RNG) and liquid fuels. The described catalysts and methods may be advantageous over conventional methods, including by reducing catalyst costs, decreasing temperature requirements and/or providing higher purity products by reducing carbon dioxide and carbon monoxide in product streams.