Boron Nanoparticles for Room‐Temperature Hydrogen Generation from Water

Abstract

solid energetic materials, including aluminum (31 kJ g −1 ). [8][9][10] In medicine, boron neutron capture therapy, a noninvasive cancer treatment using boron-10, is another important application. [ 11 ] Furthermore, boron has the highest gravimetric hydrogen generation potential among inorganic solids that can be used for chemical splitting of water, up to 277 g H 2 per kg B. For comparison, silicon, aluminum, and sodium hydride have gravimetric hydrogen generation potentials of 142, 111, and 98 g H 2 kg −1 , respectively. Thus, boron is very interesting for on demand generation of hydrogen by reaction with water.Hydrogen is an emission-free fuel with high gravimetric energy content (120 kJ g −1 ) that can be used effi ciently in well-developed proton exchange membrane (PEM) fuel cells. Hydrogen generation and storage has attracted considerable attention in the past few years because of practical limitations of conventional gas storage methods, such as high-pressure tanks, for hydrogen. On-demand generation of hydrogen from water is one means of providing hydrogen for fuel cells and other uses. The direct thermolysis of water into hydrogen and oxygen requires temperatures above 2500 K and is therefore impractical in most applications. [ 12 ] Chemical water splitting, by reacting water with a metal to produce a metal oxide and release hydrogen, is an attractive means of splitting water at much lower temperature. However, the reaction rate of metal hydrolysis usually decreases with time because of oxide formation at the surface of the metal particles. Thermodynamically, boron has great potential for on-demand hydrogen generation by reaction with water. However, boron is generally nonreactive with water; it requires either a catalyst or very high temperature to react. Several studies of water splitting by reaction with boron, using steam at elevated temperatures, were published in the past few years. Kinetics of heterogeneous, noncatalytic hydrolysis of boron (micron sized, with average diameter near 44 µm) were investigated over a range of temperatures and steam concentrations, demonstrating increased reaction rate with increasing temperature (from 500 to 800 °C). [ 13 ] Although they did not explicitly report the total hydrogen produced in each experiment, this quantity can be estimated from their plots of hydrogen fl ow rate versus time. For example, 100 mg boron and 0.5 mL min −1 water fl ow generated ≈90 mL hydrogen gas in 12 min at 700 °C. In another study, amorphous boron hydrolysis at somewhat lower temperatures (below Boron nanoparticles (BNPs) are of great interest for applications such as neutron capture therapy of cancer cells, hydrogen generation from water, and high energy density fuels. Boron is particularly interesting for chemical water splitting, because of its high gravimetric hydrogen generation potential of 277 g H 2 per kg B. However, only a few studies of water splitting by reaction with boron are available, and those have used high temperature steam with external heating. Room-temperature bo...

Synthesis and Properties of Plasmonic Boron‐Hyperdoped Silicon Nanoparticles

“…Synthesis Method : A continuous 100 W CO 2 laser pyrolysis reactor was employed to synthesize pure and doped nanoparticles as fully described before . Silane and diborane (5% in hydrogen) gases at SiH 4 :B 2 H 6 ratios ranging from 1000 to 5 were mixed with hydrogen before entering the reactor chamber.…”

Elemental Boron for Efficient Carbon Dioxide Reduction under Light Irradiation

“…To answer this question, the gas products formed upon the addition of water and also the possible surface changes of the boron catalysts during the reaction were carefully explored. Aside from the CO and CH 4 obtained by CO 2 reduction, hydrogen was also detected during the test (Figure S11), which should result from the hydrolysis of boron under the high‐temperature conditions induced by the photothermal effect . Accordingly, B(OH) 3 , the other product of boron hydrolysis, was also observed (Figures S12–S14).…”

“…Accordingly, B(OH) 3 , the other product of boron hydrolysis, was also observed (Figures S12–S14). B(OH) 3 is a volatile compound, and once it has formed on the surface of the illuminated boron sample, it will be gasified owing to the high temperature, thus keeping the boron catalyst surface exposed to the gaseous reaction species (e.g., H 2 O, CO 2 , or H 2 ). Indeed, after the test, B(OH) 3 was not observed on the boron powders (Figure d) but as a deposit on the walls of the reaction cell probably owing to the low surface temperature of the walls (Figure S12).…”

Highly active sites of NiVB nanoparticles dispersed onto graphene nanosheets towards efficient and pH-universal overall water splitting

“…Furthermore, V also facilitated to prevent the nearby metal atoms from leaching out, and thus greatly improved the durability of catalyst towards water splitting process [39]. Boron is principally exciting element for water splitting process, owing to its high gravimetric H 2 production potential of 277 g H 2 per 1000 g of B [40]. Lately, Masa and Schumann proposed that boron is helpful to boost the ECSA by generating pores on the surface of catalyst to increase the rate OER process via the leach out of its surface species in the electrolyte [41].…”