Piezo-photocatalytic reduction of nitrates to N 2 over silver dispersed on BaTiO 3 @TiO 2 .

This communication first achieved piezo-photocatalytic reduction of nitrates to N 2 through designing an Ag 2 O/BaTiO 3 @TiO 2 core-shell catalyst. The built-in electric field induced by piezoelectric polarization suppresses photoexcited carrier recombination, and simultaneously causes energy band tilting, leading to the generation of electrons with higher reducibility to directly trigger the NO 3 - reduction to ˙NO 3 2- , even without hole scavengers.