No abstract

Photocatalytic activity of pure TiO2 is limited to ultraviolet (UV) light due to the wide bandgap of anatase and rutile phases. The bandgap of high-pressure phases of TiO2 can theoretically coincide with visible light, but these phases are unstable at ambient pressure. In this work, the high-pressure TiO2-II (columbite) phase with large fractions of oxygen vacancies was stabilized by inducing plastic strain to anatase under 6 GPa. The material could absorb visible light as a consequence of bandgap narrowing by ∼0.7 eV. Formation of nanosized TiO2-II enhanced the hydrogen generation efficiency under visible light, and the efficiency improved after removing the oxygen vacancies by annealing.

High-pressure rocksalt ZnO with a band gap of 1.8 eV, which can absorb visible light.

A two-phase high-entropy oxide with orange color and good light absorbance is introduced as a photocatalyst for hydrogen production.

Wettability and the adhesion force between two silica particles were measured as a function of relative humidity. The wettability of silica particles was controlled by rehydroxylation and modification by hexamethyldisilazane and evaluated by a preferential dispersion test, heat of immersion, and water adsorption. The adhesion force between two particles was measured by atomic force microscopy using a "colloidal technique". The wettability varied from hydrophilic to hydrophobic at trimethylsilyl density ) 1.0 nm -2 as modified groups shielded the residual silanol groups and hindered the formation of a capillary bridge between the two particles. This "hindrance effect" is thought to result in the absence of a critical increase in adhesion force at high relative humidity and also the reduction of surface energy at low humidity where hydrogen bonding dominated the adhesion force.

No abstract

No abstract

No abstract