Kerf loss silicon as a cost-effective, high-efficiency, and convenient energy carrier: additive-mediated rapid hydrogen production and integrated systems for electricity generation and hydrogen storage

Base-catalyzed chemical etching of silicon in water can produce hydrogen and dissociated orthosilicic acid (SiO2(OH)(2)(2-)), suggesting that silicon can be regarded as an energy carrier. However, this process needs a large amount of low-priced silicon as the essential reactive material for cost saving and faster and high-yield hydrogen production agreeable for industrialization. In this study, high-performance hydrogen production through wet chemical etching of micrometer-sized kerf loss silicon recovered from the sawing process of solar-grade wafers is reported. Additives, including sodium metasilicate (Na2SiO3) and metasilicic acid (H2SiO3), were employed to accelerate the water splitting reaction, resulting in an optimized hydrogen production rate of 4.72 x 10(-3) g(H-2) per s per g(Si) and a yield of 92% that ranks as the best performance in the reported literature on a micrometer-sized silicon basis. In addition, a proof-of-concept example showing that kerf loss silicon is a convenient energy carrier was conducted using a kerf loss silicon-based hydrogen production reactor in coordination with either a fuel cell, which converted the supplied hydrogen to electricity, or a high-pressure tank for hydrogen storage.