Bioinspired molecular co-catalysts bonded to a silicon photocathode for solar hydrogen evolution

Hou, Yidong; Abrams, Billie; Vesborg, Peter Christian Kjærgaard; Björketun, Mårten E.; Herbst, Konrad; Bech, Lone; Setti, Alessandro M.; Damsgaard, Christian Danvad; Pedersen, Thomas; Hansen, Ole; Rossmeisl, Jan; Dahl, Søren; Nørskov, Jens K.; Chorkendorff, Ib

doi:10.1038/nmat3008

Cited by 600 publications

(489 citation statements)

References 31 publications

(17 reference statements)

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“…Furthermore, because of the abundance of the raw materials, the low fabrication cost and excellent hydrogen production performance, SiNSs have great potential for use as a photocathode material that compares favorably with other top-down-processed Si materials for PEC water-splitting systems. 7,40 …”

Section: Discussionmentioning

confidence: 99%

“…7 Here, the optical band gap energies of SiNP and SiNS were calculated from Tauc plots according to the relationship α hυ = A (hυ − E g ) 2 or α hυ = A (hυ − E g ) for the 3D SiNP and 2D SiNS, where α, hυ, A and E g are the absorption coefficient, the photon energy, a constant and the optical band gap energy 24 , respectively, as shown in Figures 5a and b. The estimated band gaps of the SiNPs (1.8 eV) and SiNS-650 (1.9 eV) are wider than the estimated band gaps of the bulk Si (1.1-1.3 eV).…”

Section: Synthesis Of Mesoporous Silicon Nanosheets From Natural Claymentioning

confidence: 99%

“…Nanostructured silicon (for example, nanowires, nanotubes and porous structures) fabricated from p-type silicon wafers and the modification of its surface have been suggested for photoelectrochemical (PEC) water reduction. [3][4][5][6][7][8][9][10] Nevertheless, high hydrogen production efficiency, the complicated fabrication steps using silicon wafers and operating conditions (for example, use of an external bias and comprising circuit) remain challenges for practical application. Direct solar water reduction from a dispersed photocatalyst is a well-known, cost-effective and simple process.…”

Section: Introductionmentioning

confidence: 99%

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All-in-one synthesis of mesoporous silicon nanosheets from natural clay and their applicability to hydrogen evolution

et al. 2016

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Silicon nanosheets have attracted much attention owing to their novel electronic and optical properties and compatibility with existing silicon technology. However, a cost-effective and scalable technique for synthesizing these nanosheets remains elusive. Here, we report a novel strategy for producing silicon nanosheets on a large scale through the simultaneous molten-salt-induced exfoliation and chemical reduction of natural clay. The silicon nanosheets thus synthesized have a high surface area, are ultrathin (~5 nm) and contain mesoporous structures derived from the oxygen vacancies in the clay. These advantages make the nanosheets a highly suitable photocatalyst with an exceptionally high activity for the generation of hydrogen from a water-methanol mixture. Further, when the silicon nanosheets are combined with platinum as a cocatalyst, they exhibit high activity in KOH (15.83 mmol H 2 per s per mol Si) and excellent photocatalytic activity with respect to the evolution of hydrogen from a water-methanol mixture (723 μmol H 2 per h per g Si).

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Section: Discussionmentioning

confidence: 99%

Section: Synthesis Of Mesoporous Silicon Nanosheets From Natural Claymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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All-in-one synthesis of mesoporous silicon nanosheets from natural clay and their applicability to hydrogen evolution

et al. 2016

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“…Solar irradiation provides a clean and unlimited energy resource to address ener gy and environmental issues [1][2][3][4]. Photocatalytic water splitting achieved on semiconductor diodes is facile and sustainable to capture, convert and store solar photons in a chemical fashion.…”

Section: Introductionmentioning

confidence: 99%

Photocatalytic water oxidation by layered Co/h-BCN hybrids

et al. 2015

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The search for new materials has progressed from metal-based photocatalysts to elemental semiconductors (C, Si, P, S, B) [11][12][13][14][15] and recently to metal-free binary materials and polymers, such as carbon nitride [16], boron carbide [17] and conjugated semiconductors [18][19][20]. These researches indicate that photon absorbing materials can be constituted by using lightweight elements such as carbon, nitrogen, and boron, opening up new opportunities for the selection of innovative and intriguing materials for artificial photosynthesis. It is of particular interest that some of these elements themselves (graphene [21], silicone [22]) or their combinations (h-BN, g-C 3 N 4 ) [23] can form layered structures with reduced thickness comparable to charge-diffusion distance, and thus if a semiconducting electronic structure was imparted in these materials, the fast separation of light-induced charge carrier would significantly benefit surface photoredox process that relied on the excitation and separation of electron-hole pairs and their subsequent participation in surface chemical reactions [24][25][26]. An interesting case of such a layered material is ternary h-BCN with tuneable ba nd gap energies between graphene (zero bandgap) and h-BN (bandgap = 5.6 eV) [27], which have the same atomic structure and share many similar properties. The hybridized phases of the two two-dimensional (2D) materials by atomic mixture of B, N, and C with broad composition ranges to create various layered semiconducting structures would produce new material functions complementary to graphene and h-BN, enabling a wide variety of electronic structures, applications and properties [28][29][30]. Such an emerging family of chemically inert and mechanically strong 2D materials practically allows the bandgap-engineered applications in heterogeneous photocatalysis by creating a medium-gap ternary semiconductor, in which the band gap, redox energy levels, p/n-type properties and surface acid-base chemistry can in principle be modulated by rational design and synthesis [31,32].A hexagonal boron carbon nitride (h-BCN) semiconductor was applied to intercalate cobalt ions to catalyze oxygen evolution reaction (OER) with light illumination, without using noble metals. The h-BCN with high specific surface area showed a strong chemical affinity towards metal ions due to the "lop-sided" densities characteristic of ionic B-N bonding, enabling the creation of metal/h-BCN hybrid layered structures with unique properties. As exemplified here by Co/h-BCN for water oxidation catalysis, after intercalating cobalt ions in the h-BCN host, the photocatalytic activity of the resultant layered hybrid is optimized due to their synergic catalysis that promotes charge separation and lowers reaction barriers. This finding promises a new nobel-metal-free nanocompsite using cost-acceptable and earth-abundant sust ances for photocatalytic OER, and enables the facile design of duel catalytic cascades by merging transition metal catalysis with h-BCN (photo)catalys...

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“…Constructing such a PEC cell requires both a photoanode and photocathode with high activity for water oxidation and reduction. Although many highly active and stable p-type photocathodes have been developed in recent years [8][9][10][11][12] , the more challenging task is to develop a photoanode that can stably oxidize water into oxygen under sunlight with high efficiency. The poor stability because of the strong oxidizing conditions and the low efficiency because of the high overpotential of four-electron water oxidation are the major challenges in designing the photoanode.…”

mentioning

confidence: 99%

Cobalt phosphate-modified barium-doped tantalum nitride nanorod photoanode with 1.5% solar energy conversion efficiency

et al. 2013

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Spurred by the decreased availability of fossil fuels and global warming, the idea of converting solar energy into clean fuels has been widely recognized. Hydrogen produced by photoelectrochemical water splitting using sunlight could provide a carbon dioxide lean fuel as an alternative to fossil fuels. A major challenge in photoelectrochemical water splitting is to develop an efficient photoanode that can stably oxidize water into oxygen. Here we report an efficient and stable photoanode that couples an active barium-doped tantalum nitride nanostructure with a stable cobalt phosphate co-catalyst. The effect of barium doping on the photoelectrochemical activity of the photoanode is investigated. The photoanode yields a maximum solar energy conversion efficiency of 1.5%, which is more than three times higher than that of state-of-the-art single-photon photoanodes. Further, stoichiometric oxygen and hydrogen are stably produced on the photoanode and the counter electrode with Faraday efficiency of almost unity for 100 min.

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Bioinspired molecular co-catalysts bonded to a silicon photocathode for solar hydrogen evolution

Abstract: The production of fuels from sunlight represents one of the major challenges to the development of a

Cited by 600 publications

References 31 publications

All-in-one synthesis of mesoporous silicon nanosheets from natural clay and their applicability to hydrogen evolution

All-in-one synthesis of mesoporous silicon nanosheets from natural clay and their applicability to hydrogen evolution

Photocatalytic water oxidation by layered Co/h-BCN hybrids

Cobalt phosphate-modified barium-doped tantalum nitride nanorod photoanode with 1.5% solar energy conversion efficiency

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