Enhancement of photoelectrochemical organics degradation and power generation by electrodeposited coatings of g-C₃N₄ and graphene on TiO₂ nanotube arrays

Abstract

Power is generated during organics photoelectrochemical degradation using electrodeposited coatings of g-C3N4 or graphene on TiO2 nanotube arrays.

Harvesting Hot Holes in Plasmon-Coupled Ultrathin Photoanodes for High-Performance Photoelectrochemical Water Splitting

“…The principal mechanism for the increase in photocurrent density for the Au@a-TiO 2 photoanode from 2.5 to 3.7 mA cm –2 upon methanol addition to the electrolyte is the current doubling effect . The current doubling effect occurs due to the methanol molecules accepting a hole from the valence band of a n-type semiconductor photoanode and then also injecting electrons into the conduction band of the photoanode . While the adsorbed water and hydroxyl ions are known to react with mobile holes, methanol is also capable of reacting with immobile trapped holes in TiO 2 . , Therefore, the increase in photocurrent density at anodic bias of 0.6 V under AM1.5G 1 sun illumination due to the addition of methanol from 2.5 to 3.7 mA cm –2 (Figure e) is due to the current doubling effect and more efficient extraction of holes from the surface of Au@a-TiO 2 .…”

Synergistic Enhancement of the Photoelectrochemical Performance of TiO2 Nanorod Arrays through Embedded Plasmon and Surface Carbon Nitride Co-sensitization

“…Methanol molecules scavenge holes from the valence band of an n-type semiconductor photoanode and then inject electrons into the conduction band of the semiconductor, causing the current to potentially double. 63 Hydroxyl ions and the adsorbed water tend to interact with free holes, and methanol can react with trapped holes in TiO 2 . 64 The observation of a near-doubling of the photocurrent (Table S4, Supporting Information) confirms that the constructed TNR− Au−TiSL−CNQD photoanode delivers photoinduced positively charged carriers to the electrolyte during the watersplitting event, which are then scavenged by methanol.…”

“…A significant photocurrent amplification effect (0.12 to 0.2 mA cm –2 ) was observed when methanol was employed as a hole scavenger in the electrolyte under 440 nm photoexcitation. Methanol molecules scavenge holes from the valence band of an n-type semiconductor photoanode and then inject electrons into the conduction band of the semiconductor, causing the current to potentially double . Hydroxyl ions and the adsorbed water tend to interact with free holes, and methanol can react with trapped holes in TiO 2 .…”