Their abundance is another aspect of non-noble metal catalysts that makes them more cost-effective. In 2022, the total worldwide reserves of platinum group metal were estimated to be approximately 70,000 metric tons; meanwhile, the total reserves of crude iron ore worldwide were estimated to be approximately 180 billion metric tons . From this, we can also see the vast difference in scarcity of the catalyst metal groups. Because noble metal catalysts are precious metals that require much effort, time, and cost to unearth and develop, replacing them with non-noble metal catalysts will help reduce the industry's dependency on scarce and costly precious metals, further maximizing the benefit of a limited budget. However, though non-noble metal catalysts are significantly cheaper than noble metal catalysts, performance-wise, there are still many challenges regarding their catalytic activity and stability, unlike noble metal catalysts.