Experimental study on photothermocatalytic CO2 reforming of benzene

To improve the conversion efficiency and reduce the CO2 emissions associated with the reforming of biomass tar to syngas, photothermal catalysts were prepared in this study through various impregnation methods. Photothermocatalytic CO2 reforming (PTCR) of benzene as a tar model compound, was conducted using the prepared Ni/TiO2-Al2O3 catalysts. The results show that the introduction of TiO2 facilitates the conversion of NiO to Ni during the photothermal reaction, while the photocatalysis of TiO2 significantly enhances the photothermocatalytic activity of the Ni/Al2O3 catalysts at low temperatures. Moreover, the methodology for catalyst preparation involving the loading of NiO before TiO2 is also beneficial to catalyst performance. However, when the mass ratio of TiO2 to Al2O3 exceeds 1, the specific surface area, pore volume, and structural stability of the catalysts are reduced. The results of PTCR experiment show the following optimal Ni/TiO2-Al2O3 catalyst preparation parameters: 25% NiO content and a TiO2/Al2O3 ratio of 3:7; 450 °C calcination temperature and a nitrogen atmosphere. The maximum benzene conversion achieved through PTCR with the 0.25Ni/0.3Ti0.7Al(M2) catalyst is 88.2%. However, a large amount of coke is deposited onto the spent catalyst surface, contributing significantly to catalyst deactivation.