Pt Single-Site Catalysts with PDO Ligands for Hydrosilylation
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Solution Overview
Problem
Heterogeneous Pt single-site catalysts for hydrosilylation face challenges with active site leaching during catalysis, limiting their reusability and application potential, despite offering improved selectivity and stability over traditional Karstedt catalysts.
Innovation Solution
A metal-ligand self-assembly method is employed to create Pt single-site centers on powdered oxide supports using 1,10-phenanthroline-5,6-dione (PDO) or bis-pyrimidyltetrazine (BMTZ) ligands, which stabilize Pt sites and reduce leaching, enhancing catalyst reusability and selectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heterogeneous Pt single-site catalysts are used for hydrosilylation, then selectivity and stability are improved, but active site leaching occurs during catalysis
Solution Approach 1:
The patent introduces oxide supports (such as Al2O3, SiO2, TiO2) as intermediary carriers to anchor Pt single atoms. The support acts as a mediator that stabilizes Pt sites through strong metal-support interactions, preventing Pt leaching into the reaction medium while maintaining catalytic activity. This resolves the contradiction by providing a stable platform that retains Pt sites during catalysis.
Solution Approach 2:
The patent creates composite catalyst systems combining Pt single atoms with oxide support materials. These composite structures integrate the high catalytic activity of Pt with the stabilizing properties of oxide supports, forming a heterogeneous catalyst that maintains structural integrity during reaction. The composite nature prevents Pt leaching while preserving selectivity and stability.
2Productivity
If Karstedt catalyst is used, then activity is high, but colloidal Pt formation deactivates the catalyst
Solution Approach 1:
The patent segments Pt into isolated single atoms dispersed on oxide supports, preventing the formation of colloidal aggregates. This atomic dispersion maintains high catalytic activity per Pt atom while eliminating the deactivation pathway associated with colloidal formation. The segmentation principle resolves the contradiction by keeping Pt in an active monatomic state.
Solution Approach 2:
The oxide support serves as an intermediary that stabilizes Pt single atoms, preventing their aggregation into colloidal particles. The support material provides anchoring sites that maintain Pt in a dispersed, active state throughout the catalytic process, thus preserving both activity and stability.
3Productivity
If homogeneous Pt complexes are used, then metal utilization efficiency is high, but separation and recycling are difficult
Solution Approach 1:
The patent uses oxide supports as intermediaries to create heterogeneous catalysts that combine the advantages of homogeneous and heterogeneous systems. The support acts as a carrier that enables easy separation by filtration or decantation while maintaining the high metal utilization efficiency characteristic of molecular catalysts. This resolves the contradiction between efficiency and ease of separation.
Solution Approach 2:
The patent creates localized Pt active sites on the oxide support surface, concentrating catalytic function at specific locations. This localized arrangement maintains high metal utilization at the active sites while the bulk support material provides easy separability. The local quality principle allows the catalyst to exhibit homogeneous-like efficiency with heterogeneous-like ease of separation.
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 resulting Pt-PDO and Pt-BMTZ catalysts exhibit excellent reusability through multiple reaction cycles with minimal site leaching, maintaining high selectivity and activity, outperforming traditional catalysts in hydrosilylation reactions.
Implementation Method 1
Hydrosilylation, the addition of a Si—H bond to a multiple bond (particularly C═C), has been of significant importance in silicon chemistry since its first report in 1947
Implementation Method 2
a metal-ligand self-assembly method is employed to create Pt single-site centers on powdered oxide supports using 1,10-phenanthroline-5,6-dione (PDO) or bis-pyrimidyltetrazine (BMTZ) ligands, which stabilize Pt sites
Data Source
AI summary
The invention describes single-site metal catalysts such as Pt single-site centers on powdered oxide supports with a 1,10-phenanthroline-5,6-dione (PDO) or bis-pyrimidyltetrazine (BMTZ) ligand on powdered MgO, Al2O3, or CeO2.