Tuning Redistribution of CuO x Nanoparticles on TiO 2 Support.

Nanoparticles exhibit unique catalytic performance, depending on their nanoscale size. However, controlling the particle size of the supported catalysts is still challenging. Here, we present a method for tunable redistribution of CuO x nanoparticles on rutile TiO 2 support by physically adding pristine TiO 2 . The redistribution is driven by the work function difference (WFD) between the TiO 2 support and the TiO 2 additive, both of which exhibit distinct values, as determined through Kelvin probe force microscopy and electron binding energy analysis. Addition of TiO 2 with lower work function (rutile) promotes electron transfer toward the CuO x /TiO 2 composite, resulting in nanoparticle aggregation, while addition of TiO 2 with higher work function (anatase) results in smaller CuO x on TiO 2 . The increase in particle size and electron density of CuO x , driven by the addition of rutile TiO 2 , promoted the complete conversion of nitrobenzene (100%) within 5 h. This is 2.7 times that of dispersed and degraded CuO x driven by mixing with anatase TiO 2 (36.9%).