A plasmonic Ag/Bi 2 WO 6 heterostructure, having Ag NPs deposited on Bi 2 WO 6 , is obtained by a hydrothermal and photodeposition method. The synthesized Ag/Bi 2 WO 6 composite exhibits strong visible light absorption with a localized surface plasmon resonance (LSPR) and shows an enhanced photoabsorption property. It is demonstrated that such a Ag/Bi 2 WO 6 heterostructure shows excellent plasmon-enhanced photocatalytic activity in the dehydrogenation of ammonia borane (NH 3 BH 3 ) solution under visible light irradiation, which is due to the results from the synergetic effect between Ag NPs and emerging W 5+ ions. More importantly, the performance of a Ag/Bi 2 WO 6 hybrid is almost eight times higher than that of sole Bi 2 WO 6 nanosheets. The introduction of LSPR of Ag in Bi 2 WO 6 improves the electrical conductivity of the composite and lowers the recombination rate of charge carriers. This study opens up the opportunity of rationally fabricating plasmonic metal/semiconductor heterostructures for highly efficient photocatalysis.

Converting solar energy to chemical energy through a photocatalytic reaction is an efficient technique for obtaining a clean and affordable source of energy. The main problem with solar photocatalysts is the recombination of charge carriers and the large band gap of the photocatalysts. The plasmonic noble metal coupled with a semiconductor can give a unique synergetic effect and has emerged as the leading material for the photocatalytic reaction. The LSPR generation by these kinds of materials has proved to be very efficient in the photocatalytic hydrolysis of the hydrogen-rich compound, photocatalytic water splitting, and photocatalytic degradation of organic dyes. A noble metal coupled with a low bandgap semiconductor result in an ideal photocatalyst. Here, both the noble metal and semiconductor can absorb visible light. They tend to produce an electron–hole pair and prevent the recombination of the generated electron–hole pair, which ultimately reacts with the chemicals in the surrounding area, resulting in an enhanced photocatalytic reaction. The enhanced photocatalytic activity credit could be given to the shared effect of the strong SPR and the effective separation of photogenerated electrons and holes supported by noble metal particles. The study of plasmonic metal nanoparticles onto semiconductors has recently accelerated. It has emerged as a favourable technique to master the constraint of traditional photocatalysts and stimulate photocatalytic activity. This review work focuses on three main objectives: providing a brief explanation of plasmonic dynamics, understanding the synthesis procedure and examining the main features of the plasmonic metal nanostructure that dominate its photocatalytic activity, comparing the reported literature of some plasmonic photocatalysts on the hydrolysis of ammonia borane and dye water treatment, providing a detailed description of the four primary operations of the plasmonic energy transfer, and the study of prospects and future of plasmonic nanostructures.

Visible-light-driven heterostructure Ag/Bi2WO6 nanocomposites were prepared using a hydrothermal method followed by the photodeposition of Ag on Bi2WO6. A photocatalyst with a different molar ratio of Ag to Bi2WO6 (1:1, 1:2 and 2:1) was prepared. The catalytic performance of Ag/Bi2WO6 towards the photocatalytic oxidation of rhodamine B (RhB) and methylene blue (MB) was explored. Interestingly, the Ag/Bi2WO6 (1:2) catalyst exhibited superior performance; it oxidized 83% of RhB to Rh-110 and degraded 68% of MB in 90 min. This might be due to the optimum amount of Ag nanoparticles, which supported the rapid generation and transfer of separated charges from Bi2WO6 to Ag through the Schottky barrier. An excess of Ag on Bi2WO6 (1:1 and 2:1) blocked the active sites of the reaction and did not produce the desired result. The introduction of Ag on Bi2WO6 improved the electrical conductivity of the composite and lowered the recombination rate of charge carriers. Our work provides a cost-effective route for constructing high-performance catalysts for the degradation of toxic dyes.

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