Electrochemical Fabrication of rGO-embedded Ag-TiO2 Nanoring/Nanotube Arrays for Plasmonic Solar Water Splitting

Abstract

HIGHLIGHTS• Reduced graphene oxide (rGO) in electrode can weaken the light scattering of plasmonic Ag nanoparticles and promote the hot electrons transfer from Ag nanoparticles to Ti substrate.• A route synergizing rGO with plasmonic Ag on TiO 2 for plasmonic solar water splitting was provided.ABSTRACT Effective utilization of hot electrons generated from the decay of surface plasmon resonance in metal nanoparticles is conductive to improve solar water splitting efficiency. Herein, Ag nanoparticles and reduced graphene oxide (rGO) co-decorated hierarchical TiO 2 nanoring/nanotube arrays (TiO 2 R/T) were facilely fabricated by using two-step electrochemical anodization, electrodeposition, and photoreduction methods. Comparative studies were conducted to elucidate the effects of rGO and Ag on the morphology, photoresponse, charge transfer, and photoelectric properties of TiO 2 . Firstly, scanning electron microscope images confirm that the Ag nanoparticles adhered on TiO 2 R/T and TiO 2 R/T-rGO have similar diameter of 20 nm except for TiO 2 R-rGO/T. Then, the UV-Vis DRS and scatter spectra reveal that the optical property of the Ag-TiO 2 R/T-rGO ternary composite is enhanced, ascribing to the visible light absorption of plasmonic Ag nanoparticles and the weakening effect of rGO on light scattering. Meanwhile, intensity-modulated photocurrent spectroscopy and photoluminescence spectra demonstrate that rGO can promote the hot electrons transfer from Ag nanoparticles to Ti substrate, reducing the photogenerated electronhole recombination. Finally, Ag-TiO 2 R/T-rGO photoanode exhibits high photocurrent density (0.98 mA cm −2 ) and photovoltage (0.90 V), and the stable H 2 evolution rate of 413 μL h −1 cm −2 within 1.5 h under AM 1.5 which exceeds by 1.30 times than that of pristine TiO 2 R/T. In line with the above results, this work provides a reliable route synergizing rGO with plasmonic metal nanoparticles for photocatalysis, in which, rGO presents a broad absorption spectrum and effective photogenerated electrons transfer. TiO 2 nanoring/nanotube arrays rGO flakes Ti substrate e − e − e − h + e − Ag/AgCl electrode Pt electrode H 2 production TiO 2 /Ag/Ag 2 O Electrochemical workstation −7.4 eV −4.2 eV −4.26 eV −4.47 eV −4 −5 −6 −7 −8 −5.98 eV Vacuum E (eV)

MXene-Derived Defect-Rich TiO2@rGO as High-Rate Anodes for Full Na Ion Batteries and Capacitors

“…Thus, various intercalation-type anodes have been explored for SIBs, such as hard carbon [ 13 ], layered titanium-based oxides [ 14 ], and molybdenum-based material [ 10 ]. Among these, TiO 2 is considered to be one of the most promising SIB anode materials due to its safety and low work potential relative to the Na + /Na redox couple [ 15 , 16 ]. However, its electrochemical performance is severely restricted by poor electron mobility (~ 10 −12 S cm −1 ) and low sodium ion diffusivity [ 9 , 17 ].…”

Defining the plasmonic cavity performance based on mode transitions to realize highly efficient device design

“…In recent years, plasmonics has attracted potential interest for use in highly efficient devices in the fields of energy conversion, fuel generation, sensors, and photonic devices. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] Understanding plasmonic mode fundamentals and properties is critical, as these factors play a defining role in material performance. [15][16][17][18][19][20][21] Factors like flexibility and simplicity in fabrication, good geometrical tolerance, large dielectric layer thicknesses with superior device characteristics, and low-cost processing are essential for developing next-generation devices with multiple applications.…”

Surface plasmon-driven photoelectrochemical water splitting of a Ag/TiO2 nanoplate photoanode

“…NP photoanode exhibits a photocurrent density of 0.07 mA cm À2 , comparable to other reported PEC systems by the TiO 2 photoanode. 59,60 Upon deposition of Ag NPs at different electrodeposition times, the photocurrent density of 1m-Ag/TiO 2 , 3m-Ag/TiO 2 , and 5m-Ag/TiO 2 NP photoanodes is drastically increased to 0.15, 0.22, and 0.35 mA cm À2 , respectively. Interestingly, the photocurrent density of the 5m-Ag/TiO 2 NP photoanode is $5 times higher than that of the pristine TiO 2 NP photoanode.…”