Masaki Saruyama

Ion exchange of ionic semiconductor nanoparticles (NPs) is a facile method for the synthesis of type-II semiconductor heterostructured NPs with staggered alignment of band edges for photoelectric applications. Through consideration of the crystallographic orientation and strain at the heterointerface, well-designed heterostructures can be constructed through ion exchange reactions. Here we report the selective synthesis of anisotropically phase-segregated cadmium sulfide (CdS)/ cadmium telluride

Changes in the crystal system of an ionic nanocrystal during a cation exchange reaction are unusual yet remain to be systematically investigated. In this study, chemical synthesis and computational modeling demonstrated that the height of hexagonal-prism roxbyite (Cu_1.8S) nanocrystals with a distorted hexagonal close-packed sulfide anion (S^2-) sublattice determines the final crystal phase of the cation-exchanged products with Co²⁺ [wurtzite cobalt sulfide (CoS) w

In the present work, we studied a unique and facile method for the drastic structural transformation of hydrophobic small CdE (E = S, Se, Te) nanoparticles into large, high-quality pencil-shaped nanoparticles through an Ostwald ripening process induced by Cl(-) and surfactants (oleic acid and oleylamine). This study revealed that Cl(-) is the effective anion for the controlled structural transformation of CdE nanoparticles. This transformation reaction can be readily extended to the formation of

Abstract Herein, PtRu solid‐solution alloy nanoparticles enable high‐performance H 2 evolution reaction cocatalysts through the transfer of knowledge from electrocatalysis to photocatalysis. Ultrafine PtRu alloy nanoparticles (1.0 ± 0.2 nm in diameter) are synthesized by using a chemical polyol method and used for electro/photo‐catalyses. Integration of PtRu nanoparticles with carbon and Al‐doped SrTiO 3 powders via liquid‐phase adsorption and successive two‐step air and H 2 annealing ensures un

ConspectusElaborate chemical synthesis methods allow the production of various types of inorganic nanocrystals (NCs) with uniform shape and size distributions. Many single-step synthesis approaches, such as the reduction of metal ions, the decomposition of metal complexes, double replacement reactions, and hydrolysis, have been adapted to promote the generation of monodisperse metal and ionic NCs. However, the question has become, how can we synthesize NCs with thermodynamically metastable phase

Cobalt doping into a Mn₃O₄ nanoparticle cocatalyst enhanced photocatalytic water splitting activity of a Mn₃O₄ cocatalyst/photocatalyst system.

Solar-driven water-splitting has been considered as a promising technology for large-scale generation of sustainable energy for succeeding generations. Recent intensive efforts have led to the discovery of advanced multi-element-compound water-splitting electrocatalysts with very small overpotentials in anticipation of their application to solar cell-assisted water electrolysis. Although photocatalytic and photoelectrochemical water-splitting systems are more attractive approaches for scaling up

Control over the composition and nanostructure of solid electrocatalysts is quite important for drastic improvement of their performance. The cation exchange reaction of nanocrystals (NCs) has been reported as the way to provide metastable crystal structures and complicated functional nanostructures that are not accessible by conventional synthetic methods. Herein we demonstrate the cation exchange-derived formation of metastable spinel Ni₃Se₄ NCs (sp-Ni₃Se<sub>4

The high overpotential of the oxygen evolution reaction is a critical issue to be overcome to realize efficient overall water splitting and enable hydrogen generation powered by sunlight. Homogeneous and stable nanoparticles (NPs) dispersed in solvents are useful as both electrocatalysts and cocatalysts of photocatalysts for the electro- and photo-catalytic oxygen evolution reaction, respectively, through their adsorption on various electrode substrates. Here, phase-segregated NiP <sub><i>x</i><

Efficient, robust and environmentally friendly cocatalysts for photocatalysts are important for large-scale solar hydrogen production. Herein, we demonstrate that a Rh-Zr mixed oxide is an efficient cocatalyst for hydrogen evolution. Impregnation of Zr and Rh precursors (Zr/Rh = 5 wt/wt%) formed RhZrO _<i>x</i> cocatalyst particles on Al-doped SrTiO₃, which exhibited 31× higher photocatalytic water-splitting activity than a RhO _<i>x</i> cocatalyst. X-ray photoelec

Seed-mediated growth synthesis has provided us with anisotropically phase-segregated CdPd sulfide heterostructured nanoparticles with seed-dependent morphologies and crystal structures.

Nanocrystal (NC) superlattices (SLs) have been widely studied as a new class of functional mesoscopic materials with collective physical properties. The arrangement of NCs in SLs governs the collective properties of SLs, and thus investigations of phenomena that can change the assembly of NC constituents are important. In this study, we investigated the dynamic evolution of NC arrangements in three-dimensional (3D) SLs, specifically the morphological transformation of NC constituents during the

Superlattices obtained by assembling inorganic nanoparticles are anticipated to constitute a novel class of materials, as they exhibit cooperative physical properties that are not observed in the isolated state of nanoparticles. Moreover, they have been investigated as a model for elucidating molecular crystallization mechanisms or as a visually accessible artificial atomic motif. In many conventional methods for fabricating superlattices, the superlattice structure typically forms as a two-dime