# US 9,751,759 B2 · Composition for hydrogen generation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,751,759 B2 - Document ID: US9751759B2 - Status: Granted - Kind: B2 - Application number: 14/432,323 - Filed: 2013-10-01 - Published: 2015-09-24 - Granted: 2017-09-05 - Earliest claimed: 2012-10-01 - Assignees: Oxford University Innovation Limited - Applicants: Oxford University Innovation Limited - Inventors: John Stuart Foord; Jingping Hu - Web page: https://patentgrep.com/patent/US9751759B2 ## CPC - C01B 3/06: by reaction of inorganic compounds containing electro-positively bound hydrogen with inorganic reducing agents - B82Y 30/00: Nanotechnology for materials or surface science, e.g. nanocomposites - C01B 33/02: Silicon (forming single crystals or homogeneous polycrystalline material with defined structure C30B) - C09C 1/28: Compounds of silicon {(C09C1/0009, C09C1/0015, C09C1/0078 take precedence)} - C01P 2002/72: by d-values or two theta-values, e.g. as X-ray diagram - C01P 2004/03: obtained by SEM - C01P 2004/62: Submicrometer sized, i.e. from 0.1-1 micrometer - C01P 2004/64: Nanometer sized, i.e. from 1-100 nanometer - Y02E 60/36: Hydrogen production from non-carbon containing sources, e.g. by water electrolysis - Y02P 20/129: Energy recovery, e.g. by cogeneration, H2recovery or pressure recovery turbines - Y10T 428/2982: Particulate matter [e.g., sphere, flake, etc.] - C01B: NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; {METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C} - B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES - C09C: TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS, TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES (treatment of materials specially adapted to enhance their filling properties in mortars, concrete or artificial stone C04B14/00, C04B18/00, C04B20/00); PREPARATION OF CARBON BLACK {; PREPARATION OF INORGANIC MATERIALS WHICH ARE NO SINGLE CHEMICAL COMPOUNDS AND WHICH ARE MAINLY USED AS PIGMENTS OR FILLERS} - C01P: INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS - Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract The invention relates to the use of nonpassivated silicon to produce hydrogen, by hydrolysis of the nonpassivated silicon. In particular, the invention relates to a composition comprising nonpassivated silicon, a process for producing a composition comprising nonpassivated silicon, and a process for producing hydrogen by reacting the composition with water. ## Claims ### Claim 1 A composition which comprises an intimate mixture of: (a) nonpassivated silicon; and (b) a dispersing agent which is a water-soluble molecular compound, a dispersant which is a water-soluble ionic compound having a heat of solution in water more negative than −40 kJmol−1, or a colloidal stabilizer which is a water-soluble polyelectrolyte. ### Claim 2 (depends on 1) A composition according to claim 1 which comprises an intimate mixture of: (a) said nonpassivated silicon; and (b) said dispersing agent which is a water-soluble molecular compound, or said colloidal stabilizer which is a water-soluble polyelectrolyte. ### Claim 3 (depends on 1) A composition according to claim 1 wherein said intimate mixture is obtained by milling (a) said nonpassivated silicon and (b) said dispersing agent, dispersant or colloidal stabilizer. ### Claim 4 (depends on 1) A composition according to claim 1 which comprises an intimate mixture of (a) said nonpassivated silicon and (b) said dispersing agent which is a water-soluble molecular compound. ### Claim 5 (depends on 1) A composition according to claim 1 which comprises an intimate mixture of (a) said nonpassivated silicon and (b) said dispersant which is a water-soluble ionic compound having a heat of solution in water more negative than −40 kJmol−1. ### Claim 6 (depends on 1) A composition according to claim 1 which comprises an intimate mixture of (a) said nonpassivated silicon and (b) said colloidal stabilizer which is a water-soluble polyelectrolyte. ### Claim 7 (depends on 4) A composition according to claim 4 which further comprises: (c) a colloidal stabilizer which is a surfactant, a water-soluble polyelectrolyte or a water-soluble non-ionic polymer. ### Claim 8 (depends on 1) A composition according to claim 1 which comprises an intimate mixture of: (a) nonpassivated silicon, (b) said dispersing agent which is a water-soluble molecular compound, and (c) said colloidal stabilizer which is a water-soluble polyelectrolyte. ### Claim 9 (depends on 1) A composition according to claim 1 which comprises an intimate mixture of: (a) nonpassivated silicon, (b) said dispersing agent which is a water-soluble molecular compound, (c) a dispersant which is a water-soluble ionic compound having a heat of solution in water more negative than −40 kJmol−1, and (d) said colloidal stabilizer which is a water-soluble polyelectrolyte. ### Claim 10 (depends on 9) A composition according to claim 9 which is obtained by milling the nonpassivated silicon with the dispersing agent, the dispersant and the colloidal stabilizer. ### Claim 11 (depends on 1) A composition according to claim 1 wherein the ionic strength of a 1.0 M aqueous solution of said dispersing agent, which solution consists of water and said dispersing agent, is less than or equal to 0.1 mol/dm3. ### Claim 12 (depends on 1) A composition according to claim 1 wherein said dispersing agent is non-ionic. ### Claim 13 (depends on 1) A composition according to claim 1 wherein said dispersing agent is a charge-neutral, covalent compound. ### Claim 14 (depends on 1) A composition according to claim 1 wherein the solubility of said dispersing agent in water at 90° C. and at 1 atmosphere of pressure is equal to or greater than 0.1 g/ml. ### Claim 15 (depends on 1) A composition according to claim 1 wherein the weight ratio of said nonpassivated silicon to said dispersing agent is from 100:1 to 1:5. ### Claim 16 (depends on 1) A composition according to claim 1 wherein said dispersing agent is a carbohydrate. ### Claim 17 (depends on 1) A composition according to claim 1 wherein said dispersing agent is sucrose or glucose. ### Claim 18 (depends on 1) A composition according to claim 1 wherein said dispersant is a metal hydroxide. ### Claim 19 (depends on 1) A composition according to claim 1 wherein said dispersant is potassium hydroxide. ### Claim 20 (depends on 1) A composition according to claim 1 wherein the weight ratio of said nonpassivated silicon to said water-soluble polyelectrolyte is from 1000:1 to 1:25. ### Claim 21 (depends on 1) A composition according to claim 1 wherein said water-soluble polyelectrolyte is negatively charged when in aqueous solution. ### Claim 22 (depends on 1) A composition according to claim 1 wherein said water-soluble polyelectrolyte is an organic polymer comprising carboxyl groups, or sulfonate groups. ### Claim 23 (depends on 1) A composition according to claim 1 wherein the water-soluble polyelectrolyte is a polymer comprising monomer units of formula (I): wherein: R1 is hydrogen or a substituted or unsubstituted C1-C6 alkyl; Y′ is COOX′, CONR′R″ or 4-phenyl-SO3X′; X′ is H or a monovalent cation; and R′ and R″ are independently hydrogen or a substituted or unsubstituted C1-C6 alkyl. ### Claim 24 (depends on 1) A composition according to claim 1 wherein the water-soluble polyelectrolyte is polyacrylic acid, polymethacrylic acid, or poly (styrene sulfonate), or a salt thereof. ### Claim 25 (depends on 1) A composition according to claim 1 wherein said water-soluble polyelectrolyte is positively charged when in aqueous solution. ### Claim 26 (depends on 1) A composition according to claim 1 wherein said water-soluble polyelectrolyte is an organic polymer comprising quaternary nitrogens or cationic nitrogen-containing groups, wherein the nitrogens are not quaternary nitrogens. ### Claim 27 (depends on 1) A composition according to claim 1 wherein the water-soluble polyelectrolyte is a polymer comprising units of formula (II) or formula (III); wherein: R2 is a substituted or unsubstituted C1-C6 alkyl; R3 is a substituted or unsubstituted C1-C6 alkyl; X′ is H or a monovalent anion. ### Claim 28 (depends on 1) A composition according to claim 1 wherein the water-soluble polyelectrolyte is poly(diallyldimethylammonium chloride), poly(L-lysine) or polyethyleneimine. ### Claim 29 (depends on 8) A composition according to claim 8 wherein said dispersing agent is sucrose or glucose and said water-soluble polyelectrolyte is polyacrylic acid or poly(diallyldimethylammonium chloride). ### Claim 30 (depends on 8) A composition according to claim 8 wherein said dispersing agent is sucrose and said water-soluble polyelectrolyte is polyacrylic acid. ### Claim 31 (depends on 9) A composition according to claim 9 wherein said dispersing agent is sucrose, the dispersant is KOH and said water-soluble polyelectrolyte is polyacrylic acid. ### Claim 32 (depends on 8) A composition according to claim 8 wherein: the weight ratio of said nonpassivated silicon to said dispersing agent is from 100:1 to 1:5; and the weight ratio of said nonpassivated silicon to said water soluble polyelectrolyte is from 1000:1 to 1:25. ### Claim 33 (depends on 8) A composition according to claim 8 wherein the weight ratio of said nonpassivated silicon to said dispersing agent to said water soluble polyelectrolyte is from 1000:10:1 to 1:5:25. ### Claim 34 (depends on 9) A composition according to claim 9 wherein the weight ratio of said nonpassivated silicon to said dispersing agent to said dispersant to said water soluble polyelectrolyte is from 1000:10:10:1 to 1:5:5:25. ### Claim 35 (depends on 1) A composition according to claim 1 wherein said composition has a Zeta potential in water of less than or equal to −18 mV. ### Claim 36 (depends on 25) A composition according to claim 25 wherein said composition has a Zeta potential of equal to or greater than 50 mV. ### Claim 37 (depends on 1) A composition according to claim 1 which has a mean particle size of less than or equal to 300 nm. ### Claim 38 (depends on 1) A composition according to claim 1 which comprises one or more encapsulates which comprise nonpassivated silicon within an organic coating. ### Claim 39 (depends on 1) A pellet for generating hydrogen, the pellet comprising a composition as defined in claim 1 encapsulated within an organic coating. ### Claim 40 (depends on 39) A pellet according to claim 39 wherein the organic coating is suitable for preventing or reducing exposure of the composition to air. ### Claim 41 (depends on 39) A pellet according to claim 39, wherein the organic coating is capable of dissolving, degrading or melting away upon exposure to water having a temperature less than or equal to 100° C. ### Claim 42 (depends on 39) A pellet according to any one of claim 39, wherein the organic coating comprises gelatine or agar. ### Claim 43 A process for producing a composition, which composition comprises: (a) nonpassivated silicon; and (b) a dispersing agent which is a water-soluble molecular compound, a dispersant which is a water-soluble ionic compound having a heat of solution in water more negative than −40 kJmol−1, or a colloidal stabilizer which is a water-soluble polyelectrolyte; which process comprises providing a sample comprising: (a) silicon; and (b) a dispersing agent which is a water-soluble molecular compound, a dispersant which is a water-soluble ionic compound having a heat of solution in water more negative than −40 kJmol−1, or a colloidal stabilizer which is a water-soluble polyelectrolyte; and, under inert conditions, reducing the mean particle size of said sample by applying a mechanical force to the sample. ### Claim 44 (depends on 43) A process according to claim 43 wherein the step of reducing the mean particle size of the sample comprises reducing the particle size by attribution (friction), impact and/or cutting. ### Claim 45 (depends on 43) A process according to claim 43 wherein the step of reducing the mean particle size of the sample comprises milling, grinding or crushing the sample. ### Claim 46 (depends on 43) A process according to claim 43 wherein the step of reducing the mean particle size of the sample is performed under an inert atmosphere and/or in an inert solvent. ### Claim 47 (depends on 46) A process according to claim 46 wherein the step of reducing the mean particle size of the sample is performed in a dry (moisture free) solvent that does not contain any OH groups. ### Claim 48 (depends on 43) A process according to claim 43 wherein (i) the step of reducing the mean particle size of the sample causes the mean particle size of said sample to be reduced to a particle size of less than or equal to 300 nm; or (ii) said silicon in said sample bears an outer layer of silicon dioxide on at least part of a surface thereof, wherein said outer layer of silicon dioxide has a first thickness, and wherein the step of reducing the mean particle size of the sample causes the average thickness of said outer layer of silicon dioxide to decrease from said first thickness to a second thickness, wherein the second thickness is less than or equal to 3.5 nm; or (iii) the step of reducing the mean particle size of the sample causes the ratio of Si to SiO2 on the surface of said silicon, as measured by X-ray photoelectron spectroscopy, to increase from a first ratio to a second ratio, wherein the second ratio is greater than the first ratio, and wherein the second ratio is at least 3:1. ### Claim 49 (depends on 43) A process according to claim 43 wherein the step of reducing the mean particle size of the sample comprises milling the sample. ### Claim 50 (depends on 49) A process according to claim 49 wherein the speed and duration of milling are selected to cause the mean particle size to be reduced to a particle size of less than or equal to 300 nm; to cause the thickness of an outer layer of silicon dioxide to be reduced to a thickness less than or equal to 3.5 nm; and/or to cause the ratio of Si to SiO2 on the surface of said sample, as measured by X-ray photoelectron spectroscopy, to increase from a first ratio to a second ratio, wherein the second ratio is greater than the first ratio, and wherein the second ratio is at least 3:1. ### Claim 51 (depends on 43) A process according to claim 43 wherein said silicon in the sample provided comprises granular silicon or coarse silicon particles. ### Claim 52 (depends on 43) A process according to claim 43 wherein said silicon in the sample provided comprises at least 90 weight % silicon. ### Claim 53 (depends on 43) A process according to claim 43 which further comprises recovering the composition thus produced, under inert conditions and coating said composition with an organic coating, to form one or more encapsulates which comprise said composition within an organic coating wherein the organic coating is suitable for preventing or reducing exposure of the composition to air. ### Claim 54 (depends on 43) A composition which is obtained by a process as defined in claim 43. ### Claim 55 (depends on 1) A process for producing hydrogen, which process comprises contacting water with a composition as defined in claim 1 and thereby producing hydrogen by hydrolysis of the nonpassivated silicon.