Manipulating Photocatalytic Oxidation Reaction Selectivity and Pathway by Simultaneous Harvesting of Ag⁺, Hot Holes, and Reactive Oxygen Species

Although Plasmon‐based photocatalyst has been employed for designing novel molecules, achieving control over the reaction selectivity has remained a challenge. Herein, the control unravels over the photocatalytic selective oxidation reaction of 4‐amino thiophenol (4‐ATP) to 4‐nitrothiophenol (4‐NTP) or 4,4′‐dimercaptoazoxybenzene (4,4′‐DMAoxB) or 4,4′‐dimercaptoazobenzene (4,4′‐DMAB) under 670 nm visible light irradiation. Oxidation reaction selectivity and pathway are shown that can be manipulated by controlling the presence of Ag + , hot holes, and reactive oxygen species (ROS) over plasmonic gold nanopopcorn (AuNPop)–tungsten oxide (WO 3 ) nanowire heterojunction. Reaction mechanism is monitored by real‐time in situ surface‐enhanced Raman spectroscopy, which demonstrates that 4‐hydroxylaminothiophenol (4‐HATP*) and 4‐nitrosothiophenol (4‐NSTP*) are the key transient intermediates. Reported data shows that in the absence of Ag + , 4‐ATP is oxidized to 4‐NTP through the hot hole and ROS‐mediated oxidation process which follows the 4‐ATP → 4‐NSTP* → 4‐NTP pathway. However, 4‐ATP oxidizes to 4,4′‐DMAoxB via simultaneous harvesting of Ag + , hot holes, and ROS, through 4‐ATP → 4‐HATP* → 4‐NSTP* → 4,4′‐DMAoxB mechanism. Additionally, 4‐ATP oxidizes to 4,4′‐DMAB via ROS‐mediated oxidation over AuNPop without WO 3 , which follows the 4‐ATP → 4‐HATP* → 4‐DMAB pathway. Reported data provides key insights for designing of new heterostructure photocatalysts for selective oxidation process.