A Comprehensive Review of Solar Photocatalysis & Photothermal Catalysis for Hydrogen Production from Biomass: from Material Characteristics to Engineering Application.

Biomass photoreforming is a promising way of producing sustainable hydrogen thanks to the abundant sources of biomass feedstocks. Solar energy provides the heat and driven force to initial biomass oxidation coupled with H2 evolution. Currently, biomass photoreforming is still far from plant-scale applications due to the lower solar energy utilization efficiencies, the low H2 yield, and the lack of appropriate photoreactors. The production of H2 from photoreforming of native biomass and platform molecules was summarized and discussed with particular attention to the prospects of scaling up the catalysis technology for mass hydrogen production. The types of photoreforming, including photocatalysis and photothermal catalysis, were discussed, consequently considering the different requirements for photoreactors. We also reviewed the photoreactors that support biomass photoreforming. Numerical simulation methods were implemented for the solid-liquid two-phase flow and inter-particle radiative transfer involved in the reaction process. Developing concentrated photothermal catalytic flowed reactors is beneficial to scale-up catalytic hydrogen production from biomass.

Experimental study on the direct firing of ceramic ware using concentrated solar energy.

In this study, we developed a solar ceramic kiln to address the problem of CO2 emissions caused by traditional ceramic ware firing processes. Ceramic specimens were fired using the proposed setup, and their properties were compared with those of an electric-fired ceramic cup (ECC). The solar-fired ceramic cup (SCC) exhibited no cracks on its surface. Its water absorption was 4.25%, open porosity was 9.93%, bulk density was 2.210 g/cm3, bending strength was 88.96 MPa, and ovalization was 1.46%. These findings suggested that the physical performance of the SCC was comparable to that of the ECC, which had water absorption of 4.03%, an open porosity of 8.79%, a bulk density of 2.180 g/cm3, an ovalization of 1.45%, and a bending strength of 72.4 MPa. The SCC achieved these results in 120 min, which was seven times faster than that of the ECC (firing time of 869 min).

SiN x /Cu Spectral Beam Splitting Films for Hybrid Photovoltaic and Concentrating Solar Thermal Systems.

Spectral beam splitting (SBS) films are crucial for the development of hybrid systems based on photovoltaic (PV) and concentrating solar thermal (CST) technologies. In this study, a novel double-layer SiN x /Cu SBS film was prepared via magnetron sputtering. This film was developed based on the linear Fresnel solar thermal technology used in PV/CST hybrid systems. The as-deposited film exhibited superior SBS properties, with a high transmittance of 72.9% and a reflectance of 89.7%. To optimize the optical properties, the thicknesses of the metal and SiN x layers were precisely controlled. The optimal thicknesses of the Cu and SiN x layers were determined to be 17 and 67 nm, respectively. Furthermore, the thermal stability of the SBS film was evaluated. When annealed at 50 °C, the surface of the SBS film became more uniform and smooth, and with increasing annealing time, the film became denser. No strong diffraction peaks of Cu were observed in the X-ray diffraction patterns because of the low content and poor crystallization of Cu. Atomic force microscopy investigations revealed the formation of a textured surface and a decrease in the root-mean-square roughness with an increase in the annealing time from 0 to 360 h. As a key component with considerable application potential in PV/CST hybrid systems, SBS films are currently an important research topic.