PNNL

Abstract

The stability of single atom catalysts against agglomeration is critical for their practical applications. High temperature can promote the strong binding of single atoms onto the substrate by forming metal-substrate bonds with enhanced thermal stability, but high temperature (> 1000°C) is typically against single atom dispersion and also incompatible with many temperature sensitive processes and substrates. Here we report using highly controllable, high temperature shockwaves to synthesize and stabilize single atoms (HT-SAs) at record-high temperatures (Ts=1500–2000 K), achieved by a periodic on-off heating pattern featuring a short on-state (55 ms) and a 10-times longer off-state. The high temperature on-state promotes single atom dispersion and stabilization by forming strong metal-substrate bonds; while the off-state critically ensures the overall stability by preventing overheating-induced atom aggregation and substrate deterioration. The repeated on-off shockwaves lead to a complete atom dispersion while keep the substrate stable despite high temperature exposure. We demonstrate the HT-SAs showing superior stability by in situ observation up to 1273 K as well as in practical applications as durable catalysts. The shockwave method is facile, ultrafast, and universal for synthesizing thermally-stable single atom dispersions (e.g., Pt, Ru, and Co) and on different substrates (e.g., carbon, C3N4, and TiO2), which opens a general route for single atom manufacturing that is conventionally challenging.