There are several reasons why certain catalytic materials are restricted:
1. Scarcity: Elements like platinum, palladium, and rhodium are critical in many catalytic processes but are also rare. Their limited availability can lead to economic and geopolitical tensions.
2. Toxicity: Some catalysts, such as those containing cadmium or mercury, pose significant health and environmental risks. Regulations often limit their use to protect human health and the environment.
3. Geopolitical Concerns: Materials like rare earth elements are predominantly sourced from specific regions, leading to supply chain vulnerabilities and strategic dependencies.
