Amorphous TiO2 beats P25 in visible light photo-catalytic performance due to both total-internal-reflection boosted solar photothermal conversion and negative temperature coefficient of the forbidden bandwidth

In this work, visible light total reflective SiO 2 @TiO 2 core-shell catalyst was synthesized by atomic layer deposition (ALD). This core-shell catalyst processing a total reflection character against full visible light favors the total effective traveling length of visible light inside the TiO 2 shell. Subsequently, higher catalyst temperature under visible light irradiation expands the light absorbing window of amorphous TiO 2 to full visible light due to its negative temperature coefficient of the forbidden bandwidth. Boosted photothermal conversion efficiency (145% that of amorphous TiO 2 ) can be achieved to exhibit a 17β-estrogen degradation rate 1.5 times that of the commercial P25 (a mixed TiO 2 crystal of 20% rutile and 80% anatase) and 2.9 times catalytic velocity that of P25. The boosted catalytic performance of SiO 2 @TiO 2 core-shell catalyst is attributed by expanded visible-light absorption, boosted photothermal conversion efficiency, and prolonged carrier lifetime.