Substitutes

Substitutes and Alternatives for Rhodium

The availability of viable substitutes is a key factor in assessing Rhodium's criticality. Across its 2 primary applications, substitution options range from commercially viable alternatives with performance trade-offs to applications where Rhodium currently has no effective substitute.

Substitution Analysis by Application

The following table details available substitutes for Rhodium across its primary applications, including the trade-offs involved:

Performance Trade-offs

In most applications, substituting Rhodium involves measurable performance penalties. Rhodium is the only commercially viable element for reducing NOx in three-way catalysts for gasoline engines; no other PGM or material can replicate its NOx reduction performance. In high-performance applications such as three-way catalytic converters, these trade-offs can be particularly significant.

Research and Development

Active research programs are underway to develop improved substitutes and to reduce the amount of Rhodium required per unit of product (thrifting). However, timelines for commercializing new alternatives typically span years to decades. The limited substitutability of Rhodium is a primary driver of its high criticality rating, prompting government-funded substitution research programs.