Building novel Ag/CeO2 heterostructure for enhancing photocatalytic activity

• Ag nanoparticle is designed to building Schottky heterojunction on CeO2 nanocube.
• The photocatalytic activity of Ag/CeO2 heterostructure is much enhanced.
• 95.33% of MB can be effectively degraded within half an hour.
• Ag as acceptor of photoelectrons blocks the recombination of electron–hole pairs.

Stable and recyclable photocatalysts with high efficiency to degrade organic contamination are important and widely demanded under the threat of the environment pollution. Ag/CeO2 heterostructure is designed as a photocatalyst to degrade organic dye under the simulated sunlight. The catalytic activity of CeO2 nanocubes (NCs) to degrade methylene blue (MB) is obviously enhanced when Ag nanoparticles (NPs) are deposited on the surface of them. The weight ratio of Ag and CeO2 in forming high efficiency catalyst, the amount of Ag/CeO2 catalyst used in degradation process, and the dye concentration and pH value of the initial MB solution are examined systematically. 95.33% of MB can be effectively degraded within half an hour when 50 mg of Ag/CeO2 catalyst in an optimal weight ratio of 1:3, is added to the 100 mL of MB solution (c0 = 1 × 10−5 mol L−1, pH 6.2). The mechanism of the enhanced catalytic activity of Ag/CeO2 heterostructure is discussed. The photocatalytic degradation rate is found to obey pseudo-first-order kinetics equations according to Langmuir–Hinshelwood model. The intermediate products in different stages during the degradation of MB are analyzed.

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