Hydroxyl-Mediated Formation of Highly Dispersed SnO₂/TiO₂ Heterojunction via Pulsed Chemical Vapor Deposition To Enhance Photocatalytic Activity

Abstract

Engineering a heterojunction on a TiO 2 surface (such as SnO 2 /TiO 2 ) is an effective strategy to enhance photocatalytic activity, by facilitating charge separation. However, the traditional fabrication for heterojunctions is usually operated in an aqueous environment, with the drawback of homogeneous nucleation of SnO 2 , which lowers photocatalytic efficiency. Herein, we develop a low-temperature pulsed chemical vapor deposition method that dispersedly deposits SnO 2 on anatase TiO 2 . By regulating the pretreatment temperatures of TiO 2 , we can tune the deposition process of SnO 2 on TiO 2 and achieve the best photocatalytic performance over deposition on 200 °C pretreated TiO 2 . Intrinsically, proper structural hydroxyls offer effective sites to boost the adsorption of Sn species via Ti−O−Sn to form a SnO 2 /TiO 2 heterojunction, which enhances photocatalysis. However, a higher surface coverage of hydroxyls from free or physically adsorbed H 2 O leads to homogeneous nucleation of SnO 2 . On the basis of these principles, we demonstrate a hydroxyl-mediated formation mechanism for a SnO 2 / TiO 2 heterojunction.

Light‐Motivated SnO2/TiO2 Heterojunctions Enabling the Breakthrough in Energy Density for Lithium‐Ion Batteries

“…[14][15][16][17][18] After coupling with light-responsive materials, the photogenerated electrons more easily flow into the SnO 2 side owing to its relatively strong electron-enrichment capability with a conduction band (CB) potential of −0.15 eV versus normal hydrogen electrode (NHE), based on energy band theory. [19,20] This result will greatly accelerate the electrochemical reactions, and meantime effectively avoid the electron-hole recombination. [21] Therefore, the SnO 2 anode hybridized with light-responsive materials is the promising solution and highly desirable for further improving its energy density to theoretical value.…”

Recent insights into SnO2-based engineered nanoparticles for sustainable H2generation and remediation of pesticides

“…128 Yu et al employed the CVD method to prepare the SnO 2 /TiO 2 heterostructure with a thickness of 810 nm. 161 Zhang et al synthesized high yields of SnO 2 nanobelts by water-assisted CVD technique. The belt-like morphology of SnO 2 showing the tetragonal rutile phase and length of 10 microns were prepared at 850 1C.…”

Experimental Study of a Novel Photoelectrochemical Hydrogen Cell Design for Clean Hydrogen Generation

“…17,18 Immobilizing TiO 2 on supportive catalysts has been conducted in many studies and has shown promising findings. 19 Different coating methods can be used for coating the photoelectrodes by TiO 2 catalysts, including electrodeposition, 20 sol−gel, 21−24 sol−spray, 25 chemical vapor deposition, 26 thermal treatment, 27 and hydrothermal treatment. 28 The fabrication and morphologies of TiO 2 have been investigated in various studies through zero-dimensional (0D), one-dimensional (1D), two-dimensional (2D), and threedimensional (3D) nanostructures.…”

“… − Titanium dioxide (TiO 2 ) is one of the most favorable catalysts that has been examined in various experimental studies for its resistivity to corrosion hasty. , It is considered a promising catalyst that could be used in visible light. , Immobilizing TiO 2 on supportive catalysts has been conducted in many studies and has shown promising findings . Different coating methods can be used for coating the photoelectrodes by TiO 2 catalysts, including electrodeposition, sol–gel, − sol–spray, chemical vapor deposition, thermal treatment, and hydrothermal treatment . The fabrication and morphologies of TiO 2 have been investigated in various studies through zero-dimensional (0D), one-dimensional (1D), two-dimensional (2D), and three-dimensional (3D) nanostructures .…”