This PDF file contains the front matter associated with SPIE Proceedings Volume 9935, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and Conference Committee listing.

Most of the traditional photocatalytic hydrogen productions were conducted under room temperature. In this work, we selected nonplasmonic Pt metal anchored on TiO₂ nanoparticles with photothermal activity to explore more efficient hydrogen production technology over the whole solar spectrum. Photothermal experiments were carried out in a carefully designed top irradiated photocatalytic reactor that can withstand high temperature and relatively higher pressure. Four typical organic materials, i.e., methyl alcohol (MeOH), trielthanolamne (TEOA), formic acid (HCOOH) and glucose, were investigated. Formic acid, a typical hydrogen carrier, was found to show the best activity. In addition, the effects of different basic parameters such as sacrificial agent concentration and the temperature on the activity of hydrogen generation were systematically investigated for understanding the qualitative and quantitative effects of the photothermal catalytic reaction process. The hydrogen yields at 90 °C of the photothermal catalytic reaction with Pt/TiO₂ are around 8.1 and 4.2 times higher than those of reactions carried out under photo or thermal conditions alone. We can see that the photothermal hydrogen yield is not the simple sum of the photo and thermal effects. This result indicated that the Pt/TiO₂ nanoparticles can efficiently couple photo and thermal energy to more effectively drive hydrogen production. As a result, the excellent ability makes it superior to other conventional semiconductor photocatalysts and thermal catalysts. Future works could concentrate on exploring photothermal catalysis as well as the potential synergism between photo and thermal effects to find more efficient hydrogen production technology using the whole solar spectrum.

Publisher’s Note: This conference presentation, originally published on 3 November 2016, was withdrawn per author request.

In the focus of this study, mixtures of commercially available TiO₂ powders were created and their photocatalytic activity concerning the acetaldehyde degradation in the gas phase was tested. Further, the lifetime of the photogenerated charge carriers was analyzed by Laser-Flash-Photolysis-Spectroscopy. The acetaldehyde degradation experiments of the mixed powders lead to positive and negative deviations from the expected weighted mean. Nevertheless, their photocatalytic activity could be correlated with the lifetime of the charge carriers. A longer charge carrier lifetime at ambient conditions correlated with a lower fractional conversion of acetaldehyde. The advantageous activities of the samples were associated with a charge transfer reaction between larger and smaller particles comparable to the antenna mechanism.¹

A hybrid material that consists of a semiconductor and a binuclear metal complex having a redox photosensitizer and a catalytic unit was employed as a photocatalyst for CO₂ reduction under visible light. It was found that this kind of hybrid was capable of reducing CO₂ into HCOOH (or CO) according to two-step photoexcitation of the semiconductor and the photosensitizer unit of the metal complex. It was found that semiconductors of TaON, CaTaO₂N, C₃N₄, and Y-Ta oxynitride became active component for this system driven by visible light (λ > 400 nm) in combination with a binuclear Ru(II) complex.

Photocatalytic overall water splitting into H₂ and O₂ is expected to be a promising method for the efficient utilization of solar energy. The design of optimal photocatalyst structures is a key to efficient overall water splitting, and the development of photocatalysts which can efficiently convert large portion of visible light spectrum has been required. Recently, a series of complex perovskite type transition metal oxynitrides, LaMg_xT _1-xO_1+3xN_2-3x, was developed as photocatalysts for direct water splitting operable at wide wavelength of visible light. In addition two-step excitation water splitting via a novel photocatalytic device termed as photocatalyst sheet was developed. This consists of two types of semiconductors (hydrogen evolution photocatalyst and oxygen evolution photocatalyst) particles embedded in a conductive layer, and showed high efficiency for overall water splitting. These recent advances in photocatalytic water splitting were introduced.

A new method to modify KCa₂Nb₃O₁₀ restacked nanohsheets with small Pt particle was developed, based on a simple electrostatic interaction between cationic precursor of Pt and negatively charged nanosheets. Compared to an ordinary impregnation method, the location of deposited Pt particles, size and valence state were different. More concretely, Pt was deposited not only on the external surface of the restacked KCa₂Nb₃O₁₀ nanohsheets, but also in the interlayer nanospace. Moreover, the deposited Pt was mainly very small (≤ 1 nm) and electron-deficient. The Pt deposited restacked KCa₂Nb₃O₁₀ nanosheets showed high photocatalytic activity for overall water splitting, which is the highest one among the nanosheets-based photocatalyst. The small particle size and deposition site of Pt are possible reasons for the high activity.

Energy is at the core of economic growth and development in the present day world. But relentless and unchecked use of harmful energy resources like fossil fuels (coil and oil), nuclear energy has taken a toll on mother nature. The energy coffers are being rapidly depleted and within a few years all of them will become empty, leaving nothing for the future generations to build on. Their constant usage has degraded the air quality and given way to land and water pollution. Scientists and world leaders have initiated a call for action to shift our dependence from currently popular energy sources to cleaner and renewable energy sources. Search for such energy sources have been going on for many years. Solar energy, wind energy, ocean energy, tidal energy, biofuel, etc. have caught the attention of people. Another such important which has become popular is 'Solar Hydrogen'. Many visionary scientists have called hydrogen the energy of the future. It is produced from water by direct or indirect use of sunlight in a sustainable manner. This paper discusses the current energy scenario, the importance of solar-hydrogen as a fuel and most importantly the scope for solar hydrogen power plants along Indian coastline.