Using Photons to Influence Catalysis on Supported Metal Catalysts

Supported metal catalysts, consisting of transition metal nanoparticles and single atoms on high surface area, insulating oxide supports, are ubiquitously used in the manufacturing of chemicals and fuels. Efforts by industrial and academic researchers focus on improving catalytic process efficiency (higher rates and/or selectivity at lower temperature and pressure) by tuning the composition of the catalytic materials. Alternatively, we (and others) have recently observed that visible photon illumination of metal nanoparticle and single atom catalysts (Pt, Cu, Ag, Rh etc.) on insulating oxide supports (Al₂O₃, SiO₂) can cause significant changes to catalytic reaction selectivity, rate, and apparent kinetic parameters. Mechanistic studies suggest that photons influence catalytic processes by redistributing charge within adsorbate-metal bonds, thereby changing elementary step energetics. Further, we have observed that using pulsed photons, rather than a continuous photon flux, allows for promoted catalytic rates with higher photon utilization efficiency. Given that modern LEDs are efficient, cheap, and programmable with on-times of sub-ms to sec and frequencies > 100 MHz, this work suggests that photon promoted or mediated chemistry may offer interesting opportunities for promoting the sustainability of chemical conversion processes. In this talk I will highlight some of our work in this area and provide some thoughts on opportunities and challenges with using light to promote or drive chemistry on supported metal catalysts.