Collective photothermal effect of Al2O3-supported spheroidal plasmonic Ru nanoparticle catalysts in the sunlight-powered Sabatier reaction

Plasmon catalysis is an interesting technology concept for powering chemical processes with light. Here, we report the use of various Al2O3-supported Ru spheroidal nanoparticles as catalyst for the low-temperature conversion of CO(2)and H(2)to CH4(Sabatier reaction), using sunlight as energy source. At high loadings of Ru spheroidal nanoparticles (5.9 % w/w), we observe a sharp increase in the rate of the sunlight powered reaction when compared to the reaction in dark at the same catalyst bed temperature. Based on our results we exclude plasmon coupling as cause, and attribute the rate enhancement to collective photothermal heating of the Al2O3-supported Ru nanoparticles.