Kai Han

Kai Han
University of Twente | UT ·  Institute for Nanotechnology (MESA+)

Doctor of Philosophy

About

20
Publications
1,611
Reads
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620
Citations
Citations since 2017
15 Research Items
474 Citations
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2017201820192020202120222023020406080100
2017201820192020202120222023020406080100
2017201820192020202120222023020406080100

Publications

Publications (20)
Article
Full-text available
By photodeposition of CrOx on SrTiO3-based semiconductors doped with aliovalent Mg(II) and functionalized with Ni/NiOx catalytic nanoparticles (economically significantly more viable than commonly used Rh catalysts), an increase in apparent quantum yield (AQYs) from ∼10 to 26% in overall water splitting was obtained. More importantly, deposition of...
Article
In the field of photocatalytic water splitting to produce sustainable hydrogen, significant breakthrough in Apparent Quantum Efficiency (AQE) has been obtained by modification of SrTiO 3 -based semiconductors. Combining doping with aliovalent Al(III) and functionalization with CrOx-promoted Rh nanoparticles, AQEs of close to 100% have been reported...
Preprint
Full-text available
By photodeposition of small quantities of CrOx on SrTiO3-based semiconductors, doped with aliovalent Mg(II) and functionalized with Ni/NiO catalytic nanoparticles (economically significantly more viable than commonly used Rh catalysts), an increase in Apparent Quantum Efficiency (AQEs) from ~10% to 26% in overall water splitting was obtained. Depos...
Article
Ni/NiO-Mg:SrTiO 3 is a promising formulation for the overall splitting of water to H 2 and O 2 when illuminated with light of 365 nm. The preparation prescribes various steps, including solid state synthesis of MgO/TiO 2 , followed by mixing with SrCO 3 and calcination at 1100 C for 10 h. Ni@NiO is deposited by impregnation, calcination, reduction...
Article
Full-text available
Functionalization of semiconductors by metallic nanoparticle is considered to be one of the most effective procedure to improve photocatalytic hydrogen production. Photodeposition is frequently used for functionalization but particle sizes and dispersions are still difficult to control. Here, Pt functionalization is achieved in a one-pot synthesis....
Article
SrTiO 3 is a promising semiconductor driving photocatalytic overall water splitting (POWS) under UV light illumination. Improving the performance of SrTiO 3 in decomposing water into H 2 and O 2 can be achieved by introducing feasible co-catalyst, such as Pt or Ni/NiO x . Though co-catalysts are employed in heterogeneous photocatalysis engineering...
Article
Full-text available
Materials used for photocatalytic overall water splitting (POWS) are typically composed of light-absorbing semiconductor crystals, functionalized with so-called cocatalytic nanoparticles to improve the kinetics of the hydrogen and/or oxygen evolution reactions. While function, quantity, and protection of such metal(oxide) nanoparticles have been ad...
Article
SrTiO3 is a well-known photocatalyst inducing overall water splitting when exposed to UV irradiation of wavelengths < 370 nm. However, the apparent quantum efficiency of SrTiO3 is typically low, even when functionalized with nanoparticles of Pt or Ni@NiO. Here, we introduce a simple solid state preparation method to control the incorporation of mag...
Article
Full-text available
The nature of the external crystal facets is critical to control the (photo)catalytic properties. 2D materials can expose only one type of crystal facet among zero-dimensional (0D), one-dimensional (1D) and two-dimensional (2D) materials. Controllable tuning of the nature of the external crystal facets of 2D materials is highly desirable but very c...
Article
Core-shell nanoparticles containing plasmonic metals (Ag or Au) have been frequently reported to enhance performance of photo-electrochemical (PEC) devices. However, the stability of these particles in water-splitting conditions is usually not addressed. In this study we demonstrate that [email protected]/* */2 core-shell particles are instable in...
Article
Full-text available
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 (...
Article
We report on the oxidation state of Pt nanoparticles when deposited on SrTiO3 or Rh-doped SrTiO3 under realistic solar water-splitting conditions. The oxidation state was investigated using state-of-the-art analysis of the reaction in a continuously stirred tank reactor (CSTR) connected to a micro gas chromatograph equipped with a pulsed discharge...
Article
Full-text available
A hybrid system with a coordinative interaction between a cobalt complex of a N2S2-tetradentate ligand and CdTe quantum dots displayed a high activity (initial TOF 850 h−1) and improved stability (TON 1.44 x 104 based on catalyst over 30 h) for the photochemical H2 generation from water, with a quantum efficiency of 5.32% at 400 nm.
Article
The development of energy-efficient, cost-effective and durable photocatalytic systems for water splitting is one of the scientific problems that must be solved before the successful transformation from a fossil fuel-based economy to a solar fuel-based economy can be realized. Conventional photocatalytic systems are generally divided into heterogen...
Article
Full-text available
Self-assembled molecular iron and cobalt catalysts (MP4N2, M = Fe, Co) bearing a multihydroxy-functionalized tetraphosphine ligand electrocatalyze H2 generation from neutral water on a mercury electrode at −1.03 and −0.50 V vs. NHE, respectively. Complex CoP4N2 displays extremely low overpotential (Eonset = 80 mV) while maintaining high activity an...
Article
Bio-inspired noble-metal-free supramolecular systems were constructed by host-guest inclusions of an FeFe-hydrogenase mimic and an organic dye into cyclodextrins respectively, which give typically a ninefold increase in the TON, a sixteenfold enhancement in the quantum efficiency, and a threefold extension in lifetime as compared to the same system...

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Projects

Project (1)
Project
- Understanding morphology and oxidation state of co-catalytic nanoparticles when prepared by photodeposition on (doped) semiconductor surfaces - Understanding transients in composition of such nanoparticles upon illumination, initiating overall water-splitting to hydrogen and oxygen