Jae Sung Lee

Heterojunction electrodes were fabricated by layer-by-layer deposition of WO3 and BiVO4 on a conducting glass, and investigated for photoelectrochemical water oxidation under simulated solar light. The electrode with the optimal composition of four layers of WO3 covered by a single layer of BiVO4 showed enhanced photoactivity by 74% relative to bare WO3 and 730% relative to bare BiVO4. According to the flat band potential and optical band gap measurements, both semiconductors can absorb visible

Photoelectrochemical (PEC) cells for solar-energy conversion have received immense interest as a promising technology for renewable hydrogen production. Their similarity to natural photosynthesis, utilizing sunlight and water, has provoked intense research for over half a century. Among many potential photocatalysts, BiVO₄ , with a bandgap of 2.4-2.5 eV, has emerged as a highly promising photoanode material with a good chemical stability, environmental inertness, and low cost. Unfortu

A monoclinic BiVO4 lattice was doped with phosphate to enhance photoelectrochemical and photocatalytic water oxidation activity under visible light by a factor of about 30 compared with pristine BiVO4. Electrochemical impedance spectroscopy measurements and density functional calculations revealed that much improved charge transfer characteristics of BiVO4 are mainly responsible for the greatly enhanced photoelectrochemical activity. Detailed facts of importance to specialist readers are publish

MoS₂ becomes an efficient and durable nonprecious-metal electrocatalyst for the hydrogen evolution reaction (HER) when it contains multifunctional active sites for water splitting derived from 1T-phase, defects, S vacancies, exposed Mo edges with expanded interlayer spacings. In contrast to previously reported MoS₂ -based catalysts targeting only a single or few of these characteristics, the all-in-one MoS₂ catalyst prepared herein features all of the above activ

Recycling CO2 as a renewable carbon source for the production of high-value fuels and chemicals has drawn global attention lately as a promising method to mitigate climate change and lessen dependence on fossil fuels. Among the available CO2-recycling options, catalytic CO2 hydrogenation is the most realistic and attractive choice if the hydrogen is produced using a renewable energy source. Depending on the nature of the catalyst, CO2 hydrogenation has distinct reaction pathways, and various val

The visible-light-induced water oxidation ability of metal-ion-doped BiVO(4) was investigated and of 12 metal ion dopants tested, only W and Mo dramatically enhanced the water photo-oxidation activity of bare BiVO(4); Mo had the highest improvement by a factor of about six. Thus, BiVO(4) and W- or Mo-doped (2 atom %) BiVO(4) photoanodes about 1 μm thick were fabricated onto transparent conducting substrate by a metal-organic decomposition/spin-coating method. Under simulated one sun (air mass 1.

Hexagonal WO3 (hex-WO3) nanowires with high aspect ratio and crystallinity have been prepared for the first time by a microwave-assisted hydrothermal method. By using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and high resolution transmission electron microscopy, the phase and morphology of the products were identified, which were controlled by reaction temperature, holding time and added salts. Uniform hex-WO3 nanowires with a diameter of 5–10 nm and lengt

A bulk heterojunction photocatalyst of interfacing CaFe(2)O(4) and MgFe(2)O(4) nanoparticles is highly active for oxidative degradation of isopropyl alcohol and hydrogen production from water under visible light, because the exciton easily reaches the interface and dissociates to minimize recombination.

An ultrathin (ca. 2 nm) amorphous FeOOH overlayer was deposited conformally on a hematite nanostructure by a simple solution-based precipitation method, to generate an oxygen evolution cocatalyst for efficient solar water splitting. This uniform and highly conformal coating of the ultrathin metal oxyhydroxide is rare and is distinguished from the layers prepared by other conventional methods. With the FeOOH overlayer as the cocatalyst, the water oxidation photocurrent of hematite increased by a

A 1D ZnFe₂O₄ photoanode is treated under a hydrogen or vacuum atmosphere to improve the photoelectrochemical water oxidation activity up to 20 times. This post-treatment creates oxygen vacancies in the ZnFe₂O₄ lattice that serve as a source of electron donors and passivates surface trap sites, and as a result improves charge transfer.