A selectively exposed crystal facet-engineered TiO₂ thin film photoanode for the higher performance of the photoelectrochemical water splitting reaction

Abstract

In the present study, selectively exposed (101)-crystal facet engineered TiO2 photoanode is investigated for the higher efficiency of hydrogen evolution reaction. Till date, even the photoelectrochemical performance (PEC) depending on the exposed crystal facet have been calculated and demonstrated in the semiconducting microcrystals, selectively exposed crystal facet of photocatalyst thin films has not been reported yet. Herein, we demonstrate TiO2 thin film photoanode with 100%-exclusively exposed crystal facet and suggest the methodology for metal oxide thin film photoanode with selectively exposed crystal facet. Selectively exposed crystal facet-manipulated metal oxide thin film photoanode is fabricated over the pre-synthesized microcrystals through a three-step strategy: 1) hydrothermal synthesis of microcrystals, 2) positioning of microcrystals via polymer-induced manual assembly, and 3) fabrication of selectively exposed crystal facet of TiO2 thin film through secondary growth hydrothermal reaction. Based on the synthesis of representative TiO2 microcrystals with dominantly exposed (101), (100) and (001) crystal facet, selectively exposed crystal faceted TiO2 thin film photoanode is comparatively investigated for practical PEC performance. The photocurrent density of selectively exposed (101) crystal faceted TiO2 thin film photoanode is determined as 0.13 mA cm -2 and produce 18% of incident photon-to-current conversion efficiency at 0.65 V Ag/AgCl potential under AM 1.5 G illumination. Its photoelectrochemical hydrogen production reached to 0.07 mmol cm -2 for 12 hrs, which is higher than those of (100) and (001) faceted photoelectrode.

(040)‐Crystal Facet Engineering of BiVO4 Plate Photoanodes for Solar Fuel Production

“…Based on the concept of surface-bound species, [ 37 ] two active sites are required for two water molecule adsorption during the oxygen evolution process. [ 39 ] Especially, based on that the Nyquist plots is attributed to the interfacial charge transfer kinetics, the recombination resistance at the interface between the surface of BVO thin fi lm photoanode and electrolyte solution increases in the following order: (040)-BVO < PF-BVO < SL-BVO in Figure S16 (Supporting Information). Based on our observations, the origin of the highly effi cient solar fuel production on (040)-BVO was due to a synergistic effect between the enhanced charge mobility and local bonding geometry to get lower energy barrier for the effi cient charge transfer through the interface.…”

Silicon Wafers with Facet‐Dependent Electrical Conductivity Properties

“…[1][2][3][4][5][6] These interesting semiconductor properties can be explained in terms of the presence of an ultrathin surface layer having varying degrees of band bending for different surface planes.T his effect controls the relative obstacle of charge transport through asemiconductor crystal depending on the points of electrical contacts.S uch af eature is highly useful for electronic component design. [1][2][3][4][5][6] These interesting semiconductor properties can be explained in terms of the presence of an ultrathin surface layer having varying degrees of band bending for different surface planes.T his effect controls the relative obstacle of charge transport through asemiconductor crystal depending on the points of electrical contacts.S uch af eature is highly useful for electronic component design.…”

Controlled synthesis of m-BiVO4 dendrites for enhanced photocatalytic activity

“…55% of RhB was removed when the photocatalytic degradation time is 240 min, and the degradation rate of the counterpart is 40%. The excellent photocatalytic activity of the as-prepared m-BiVO 4 dendrites might be contributed to the special morphology which could effectively enhance the utilization of light [12][13][14][15][16][17]. The inset in Fig.…”