Surface activation of platinum group metal clusters for efficient and durable oxygen reduction in proton exchange membrane fuel cells.

The article focuses on a surface activation strategy based on nitrogen coordination-induced strong metal–support interaction (SMSI) to enhance the oxygen reduction reaction (ORR) catalytic activity and durability of platinum group metal (PGM) clusters for proton-exchange membrane fuel cells (PEMFCs). Using rhodium (Rh) as a primary example, Rh atomic clusters embedded in nitrogen-doped porous carbon exhibit quasi-single-atom active sites with ORR performance comparable to commercial platinum catalysts but with superior stability. This approach overcomes the instability issues of single-atom catalysts and low activity of conventional PGM nanoparticles by combining their advantages through strong coordination between surface metal atoms and nitrogen in the carbon support. The strategy is also demonstrated to be effective for other PGMs such as iridium, ruthenium, and platinum, offering a promising pathway to reduce PEMFC reliance on platinum.