Enhancing photocatalytic visible-light-driven oxidation of NOx over Mott-Schottky Ag/SnO2 nanorod heterojunctions

Nitrogen oxides (NOx) is formed by primary emission from diesel engine vehicles. In this study, we synthesized and applied the photocatalytic effect over Mott-Schottky Ag/SnO2 nanorod heterojunctions toward NOx removal under visible light. In detail, the presence of Ag NPs in the Ag/SnO2 nanorod heterojunction, the number of electrons participating in the catalysis is enhanced due to the localized surface plasmon resonance (LSPR) of Ag NPs. In addition, the potential of the reducing region of SnO2 is also changed, thereby creating favourable conditions for the photocatalysis. We determined that 1.5% Ag/SnO2 nanorod heterojunction is the best sample with NO (500 ppb) photodegradation efficiency of 50.64% under visible light irradiation. Moreover, Ag/SnO2 nanorod heterojunction has an excellent stability after undergoing five times recycling and is highly applicable in practical applications with a high NO degradation and low NO2 conversion yield. The Mott-Schottky plots, Tauc plots, and trapping tests were used to build the energy scheme of the Ag/SnO2 heterojunction.