It seems that when it comes to bimetallic catalysts, those with a less than perfect structure perform better than their cleaner-cut counterparts. Dion Vlachos of the University of Delaware and colleagues have demonstrated in the journal Nature Communications how a patched architecture may give a more effective catalytic reaction than that seen with a conventional core-shell structure. Moreover, imperfect structures are easier to make, so that simplifies the overall process of catalyst generation. Platinum catalysts with patches of nickel dopant on the surface rather than a consistent, smooth shell were used to demonstrate efficacy in ammonia degradation. "What we have is bifunctional activity, where flat nickel 'terraces' catalyze the breaking of nitrogen-hydrogen bonds, and nickel ‘edges’ drive the pairing of nitrogen atoms," explains Vlachos. "What we thought of as a 'defective' catalyst was actually two to three orders of magnitude better than the so-called 'perfect catalyst',"” he adds. "This finding opens up broad new horizons for materials design."
For catalysts, worse can be better