Transient Behavior of Ni@NiOx Functionalized SrTiO3 in Overall Water Splitting
نویسندگان
چکیده
Transients in the composition of Ni@NiO x core-shell co-catalysts deposited on SrTiO3 are discussed on the basis of state-of-the-art continuous analysis of photocatalytic water splitting, and post-XPS and TEM analyses. The formation of excessive hydrogen (H2:O2 ≫ 2) in the initial stages of illumination demonstrates oxidation of Ni(OH)2 to NiOOH (nickel oxyhydroxide), with the latter catalyzing water oxidation. A disproportionation reaction of Ni and NiOOH, yielding Ni(OH)2 with residual embedded Ni, occurs when illumination is discontinued, which explains repetitive transients in (excess) hydrogen and oxygen formation when illumination is reinitiated.
منابع مشابه
Atomic Level In-situ Characterization of NiO-TiO2 Photocatalysts under Light Irradiation in Water Vapor
Photocatalysts are important for environmental cleanup of undesirable organic compounds and have potential applications for solar fuel generation either through water splitting or CO2 reduction [1]. It is now recognized that atomic level in-situ observations of catalytic materials are critical for understanding the structure-reactivity in catalysts. For photocatalysts, this requires that the sy...
متن کاملParameterization of Water Electrooxidation Catalyzed by Metal Oxides Using Fourier Transformed Alternating Current Voltammetry.
Detection and quantification of redox transformations involved in water oxidation electrocatalysis is often not possible using conventional techniques. Herein, use of large amplitude Fourier transformed ac voltammetry and comprehensive analysis of the higher harmonics has enabled us to access the redox processes responsible for catalysis. An examination of the voltammetric data for water oxidat...
متن کاملAn Oxygen-Insensitive Hydrogen Evolution Catalyst Coated by a Molybdenum-Based Layer for Overall Water Splitting.
For overall water-splitting systems, it is essential to establish O2 -insensitive cathodes that allow cogeneration of H2 and O2 . An acid-tolerant electrocatalyst is described, which employs a Mo-coating on a metal surface to achieve selective H2 evolution in the presence of O2 . In operando X-ray absorption spectroscopy identified reduced Pt covered with an amorphous molybdenum oxyhydroxide hy...
متن کاملImproving BiVO4 photoanodes for solar water splitting through surface passivation.
BiVO4 has shown great potential as a semiconductor photoanode for solar water splitting. Significant improvements made during recent years allowed researchers to obtain a photocurrent density of up to 4.0 mA cm(-2) (AM1.5 sunlight illumination, 1.23 VRHE bias). For further improvements of the BiVO4 photoelectrodes, a deep understanding of the processes occurring at the BiVO4-H2O interface is cr...
متن کاملThree-Phase Modeling of Dynamic Kill in Gas-Condensate Well Using Advection Upstream Splitting Method Hybrid Scheme
Understanding and modeling of three-phase transient flow in gas-condensate wells play a vital role in designing and optimizing dynamic kill procedure of each well that needs to capture the discontinuities in density, geometry, and velocity of phases but also the effect of temperature on such parameters. In this study, two-phase Advection-Upstream-Splitting-Method (AUSMV) hybrid scheme is extend...
متن کامل