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Handbook of Biomass Valorization for Industrial Applications


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light radiations for reactions below 170 nm optical wavelength. But, both glass and quartz are not really stable under some specific temperature and alkaline conditions. Therefore, some polymeric materials are used for building photocatalytic reactors such as PFA, FEP, PDMS, and PMMA. Among these, PFA and PEP as fluoro materials showed better performance in terms of activity, stability, and cost. Moreover, as a big advantages of these materials is to absorb both types of light radiations (visible and UV). Fabrication of photocatalytic reactors with these materials is easy and low cost which provides better stability also.

      1.3.6 Solar Fuel Synthesis Through Photocatalysis

      To reduce the dependency on fossil fuels and environmental pollution caused due to consumption of these fuels, renewable fuel production from biomass is in great demand and gained the focus of attention of academic and industrial researchers since the last decade.

      1.3.7 Photocatalytic Reforming

      There are many technologies available for biomass utilization to produce valuable products such as seam reforming, dry reforming, pyrolysis, gasification, supercritical water reforming, partial oxidation, autothermal reforming, aqueous phase reforming, photocatalytic reforming, etc. Among all of them, photocatalytic reforming is a different technique because it is totally supported by solar energy as solar radiation energy is available free of cost on this globe. Photocatalytic reforming is recognized as a sustainable and promising process to convert solar energy into hydrogen as chemical energy for various necessary applications. Likewise, utilizing biomass via photocatalytic reforming is an effective route to convert to biofuel to chemical fuels such as clean hydrogen production which is a feasible alternate of fossil fuels for future development. Photocatalytic reforming minimizes the problems occurring in thermo-catalytic conversion of biomass reaction conditions and also combines solar energy with biofuels which is quite beneficial for our environment because it reduces the possibility of air and water pollution. A similarity is found in the mechanism of photocatalytic reforming of biomass and other materials. The substrates used as photocatalytic substrates are mainly semiconductors in which electron-hole pairs are formed to interact with incident solar heat waves and utilized in oxidative and reduction steps of photocatalytic reaction which is mostly based on titania catalysts. But, the addition of unwanted electron-hole pairs in the reactions is a drawback in the case of titania catalysts because they are the reason to achieve lower efficiency in photocatalytic reactions. Therefore, to improve the efficiency of the some specific photocatalysts, the addition of some metal particles in nano-size over the surface of titania is required so that the unwanted electrons can be trapped and the paring of electron-holes can be minimized. It has been seen that the gold oriented nanoparticles with the combination of platinum/palladium provides high conversion of some organic compounds like oxidation of alkanes, polylols, CO, and alcohols. But, these gold based photocatalysts are very costly and not feasible from the economic point of view. However, silver based nanoparticles are getting much attention by the researchers who are working in this field of photocatalysis due to wide range of applications such as sensors, catalysts, and microelectronics. The effects of gold/silver loadings with proper specified heat treatment over TiO2 based photocatalysts showed better catalytic activity for the production of hydrogen and other valuable by-products.

S. no. Biomass substrate with conditions Conversion Products (Y = yield, S = selectivity) Light radiation Photocatalyst
1. Glucose 89% H2 = 220 μmol (Y) Ultraviolet NiO/NaTaO3
2. Glucose 29% H2 = 100 μmol (Y) Visible Pt/ZnS-ZnIn2S4
3. Glucose 83% H2 = 4.8 mmol (Y) Ultraviolet Pt/TiO2
4. Glucose 11% Glucaric acid + Gluconic acid + Arabitol = 71% (S) Ultraviolet TiO2
5. HMF 20% FDC = 22% (S) Ultraviolet TiO2
6. Glucose 7% Glucaric acid + Gluconic acid = 87% (S) Ultraviolet Cr/TiO2/zeolite
7. Glucose 100% H2 = 5,460 μmol (Y) Visible Ru-LaFeO3/Fe2O3
8. Glucose 65% H2 = 850 μmol (Y) Xenon Lamp Rh/TiO2
9. Arabinose + Glucose 13.28% H2 = 60.1 μmol (Y)