Plasmonic silver (Ag)-based photocatalysts for H2 production and CO2 conversion: Review, analysis and perspectives

In this review, the most recent developments regarding highly efficient photocatalytic composites containing plasmonic silver (Ag) are reported, with a detailed description of their Surface Plasmon Resonance (SPR) mechanisms, structural and electrochemical properties and their application in renewable fuel production through photocatalysis, specifically through water splitting towards hydrogen production and through carbon dioxide reduction towards the production of methane (CH4), methanol (CH3OH) and other chemicals. Firstly, an analysis of plasmonic composite properties shows their advantages for photocatalytic applications: enhancements induced by the localized SPR effect increase photo-charge production near the semiconductor surface with improved charge separation and light responsiveness in a wider spectral range. Next, a review of the effects of silver integration on the material properties of semiconductors, examined via physicochemical characterization techniques, is performed. Then, a critical view of recent photocatalysis applications of silver composites for the generation of hydrogen and carbon dioxide conversion products is presented, with a focus on the effect of silver integration on their mechanisms and performance. Finally, applications of the generated hydrogen and the CO2 reduction-produced CH4 and CH3OH are explored.