Doping SnO2 with metal ions of varying valence states: discerning the importance of active surface oxygen species vs. acid sites for C3H8 and CO oxidation

To elucidate the valence state effect of doping cations, Li + , Mg 2+ , Cr 3+ , Zr 4+ and Nb 5+ with radii similar to Sn 4+ (CN = 6) were chosen to dope tetragonal SnO 2 .