The disclosure provides a system and a method for reducing hazardous gases, including PHGs, through one or more photocatalysts in a filter system. A microstructure of the photocatalytic filter can be formed using biological systems as a template for the photocatalysts to be deposited thereon. The biological system can be removed by heat, oxidation, or by chemical processes to leave the photocatalytic template as a filter for the gases. In various embodiments, multiple photocatalysts can be activated at different wavelengths to filter different gases, or multiple photocatalysts can be activated at the same wavelength to filter different gases, or a photocatalyst can be activated at different wavelengths to filter different gases, or some combination thereof. The activation can be sequential or concurrent. For multiple layers of photocatalysts, the sequence of the photocatalysts can be arranged to reduce damaging output from an upstream photocatalyst to one or more downstream photocatalysts.

A catalyst carrier, an electrode catalyst, an electrode including the catalyst, a membrane electrode assembly including the electrode, and a fuel cell including the membrane electrode assembly. The catalyst carrier includes a carbon material having a chain structure including a chain of carbon particles, and an oxide-carbon composite particle in which a carbon particle encloses a particle of an oxide of a group IV element on the periodic table, the oxide-carbon composite particle being contained in the carbon material. The catalyst carrier has a BET specific surface area of 450 to 1100 m.sup.2/g.

Systems and methods of synthesizing nanoparticles on substrates using rapid, high temperature thermal shock. A method involves depositing micro-sized particles or salt precursors on a substrate, and applying a rapid, high temperature thermal pulse or shock to the micro-sized particles or the salt precursors and the substrate to cause the micro-sized particles or the salt precursors to become nanoparticles on the substrate. A system may include a rotatable member that receives a roll of a substrate sheet having micro-sized particles or salt precursors; a motor that rotates the rotatable member so as to unroll consecutive portions of the substrate sheet from the roll; and a thermal energy source that applies a short, high temperature thermal shock to consecutive portions of the substrate sheet that are unrolled from the roll by rotating the first rotatable member. Some systems and methods produce nanoparticles on existing substrate. The nanoparticles may be metallic, ceramic, inorganic, semiconductor, or compound nanoparticles. The substrate may be a carbon-based substrate, a conducting substrate, or a non-conducting substrate. The high temperature thermal shock process may be enabled by electrical Joule heating, microwave heating, thermal radiative heating, plasma heating, or laser heating.

This invention relates to a carrier for immobilizing a biocatalyst including a Fe.sub.2O.sub.3 yolk-shell structure, to an immobilized enzyme using the carrier, and to realizing an increase in the stability of the enzyme and stability in organic solvents by cross-linking the enzyme. According to this invention, the carrier for immobilizing a biocatalyst and the enzyme immobilized thereon can be reused, have increased stability, facilitate the control of reactivity, pH, and temperature, and can be widely useful in various biochemical engineering industries.

Disclosed is a method for preparing a material of plant origin rich in phenolic acids, including at least one metal, including: preparing a material of plant origin chosen from: aquatic plants; materials rich in tannins; materials rich in lignin; and obtaining a material of plant origin, rich in phenolic acids, in which the ratio of the intensity of the vibration band of the C═O bond of the COOH group and the intensity of each of the vibration bands the aromatic ring determined in FT-IR is between 0.5 and 4. The material of plant origin is brought into contact with an effluent including from 0.1 to 1000 mg/l of at least one metal, thus obtaining a material of plant origin rich in phenolic acids including from 1 to 30% by weight of at least one metal relative to the total weight of the material.

Shaped porous carbon products and processes for preparing these products are provided. The shaped porous carbon products can be used, for example, as catalyst supports and adsorbents. Catalyst compositions including these shaped porous carbon products, processes of preparing the catalyst compositions, and various processes of using the shaped porous carbon products and catalyst compositions are also provided.

The manufacturing method of titanium dioxide solution includes: mixing choline chloride, urea, boric acid, and titanium tetrachloride to form a first solution, wherein a molar concentration ratio of choline chloride to urea is 1:2, a molar concentration of titanium tetrachloride is 0.2 M to 0.4 M, and weight/volume of boric acid is 5 g/300 ml to 15 g/300 ml; and heating the first solute ion to form a second solution, wherein the second solution contains carbon/nitrogen doped titanium dioxide. In the manufacturing method of the present disclosure, the deep eutectic solution formed by choline chloride and urea may be used as a solvent, and may also be used as a carbon source and/or a nitrogen source. Therefore, titanium dioxide may be doped with carbon and/or nitrogen during the formation process.

The invention relates to a method of preparing a catalytic composition comprising at least one non-noble metal from group VIII and at least one metal from group VIB of the periodic table. The invention also relates to the catalytic composition thus produced, which has a high specific activity in reactions involving the hydroprocessing of light and intermediate fractions, preferably in reactions involving the hydrotreatment of hydrocarbon streams, including hydrodesulphurisation (HDS), hydrodenitrogenation (HDN) and hydro-dearomatisation (HDA).

High surface area 3D mesoporous carbon nanocomposites can be derived from Zn dust and PET bottle mixed waste with a high surface area. Simultaneous transformation of Zn metal into ZnO nanoparticles and PET bottle waste to porous carbon materials can be achieved by thermal treatment at preferably 600 to 800° C., and reaction times of from 15 to 60 minutes, after optionally de-aerating the reaction mixtures with N.sub.2 gas. The waste-based carbon materials can have surface areas of 650 to 725 m.sup.2/g, e.g., 684.5 m.sup.2/g and pore size distributions of 12 to 18 nm. The carbon materials may have 3D porous dense layers with a gradient pore structure, which may have enhanced photocatalytic performance for degrading, e.g., organic dyes, such as methylene blue and malachite green. Sustainable methods make ZnO-mesoporous carbon materials from waste for applications including photocatalysis, upcycling mixed waste materials.

Disclosed is a composite catalyst, comprising carbon in a continuous phase and Raney alloy particles in a dispersed phase. The Raney alloy particles are dispersed evenly or unevenly in the carbon in a continuous phase, and the carbon in a continuous phase is obtained by carbonizing at least one carbonizable organic substance. The catalyst has good particle strength, high catalytic activity, and good selectivity.