Nanoscale Engineering in the Development of Photoelectrocatalytic Cells for Producing Solar Fuels

Ampelli, Claudio; Genovese, Chiara; Centi, Gabriele; Passalacqua, Rosalba; Perathoner, Siglinda

doi:10.1007/s11244-016-0547-5

Cited by 26 publications

(24 citation statements)

References 104 publications

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“…However, the development of photoanodes for practical PEC devices imposes a series of constrains that greatly limit the range of the possible materials and their characteristics. For example, it is necessary to have thin films with a specific ordered nanostructure to transport the photo-generated charges (H + /e − ) during water oxidation to the other side of the cell, where they may combine to generate hydrogen or reduce CO 2 to fuels and chemicals [6,7]. For this reason, thin films based on an ordered array of verticallyaligned TiO 2 nanotubes still represent an important sector of development of PEC devices, even though a further engineering [8] is needed to optimize their performances.…”

Section: Introductionmentioning

confidence: 99%

Role of CuO in the modification of the photocatalytic water splitting behavior of TiO2 nanotube thin films

Brito

Tavella

Genovese

et al. 2018

Applied Catalysis B: Environmental

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The role of CuO nanoparticles decorating TiO 2 nanotubes (TNT) thin film photoanodes in the behavior of photoelectrocatalytic (PEC) cells for water splitting reaction is investigated. CuO is present mainly as small nanoparticles of few nanometer decorating the internal walls of the TiO 2 nanotubes. Their presence improves i) the photocurrent behavior, ii) the H 2 generation rate by water splitting in a full PEC device (without application of a bias) and iii) the solar-to-hydrogen (STH) efficiency. The increase is about 20% with respect to parent TNT photoanodes using open spectrum light from a solar simulator and about 50% increase using AM 1.5G filtered light from a solar simulator. An STH efficiency over 2% in the full PEC cell is observed in the best conditions. IPCE (incident photon to current conversion efficiency) measurements clearly evidence that the presence of CuO nanoparticles induce an enhanced IPCE in the 300-340 nm region. The increase in the performances in water splitting is mainly associated to the transient generation of a p-n junction between the Cu x O nanoparticles and TNT upon illumination, which enhances photocurrent density by promoting charge separation.

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Section: Introductionmentioning

confidence: 99%

Role of CuO in the modification of the photocatalytic water splitting behavior of TiO2 nanotube thin films

Brito

Tavella

Genovese

et al. 2018

Applied Catalysis B: Environmental

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162

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“…Thecell operates at 20 8 8Cand atmospheric pressure.With respect to the cell reported by Kordali et al [8] we may note two main differences:1 )ino ur cell, the half-cell where the reduction of N 2 to NH 3 occurs,o perates in the gas-phase (electrolyte-less conditions;w ea lready demonstrated the feasibility and advantages of this approach for CO 2 conversion [14] ), while the cell of Kordali et al [8] operates in the presence of al iquid electrolyte;2 )these authors used a2m KOHa queous solution as the electrolyte,w hich shows limits when N 2 is replaced by air as CO 2 in air may react with KOHt of orm K 2 CO 3 .I na ddition, often stability of the electrodes is low under these strong basic conditions.The cell presented in Figure 1operates instead with adiluted concentration of KHCO 3 (only in the half-cell for water electrolysis, while electrolyte-less conditions are present in the cathode half-cell, where the reduction of N 2 to NH 3 occurs.I nt hese conditions,d on ot exists the problem of formation of potassium-carbonate by reaction with CO 2 .I ts hould be also commented that stronger basic conditions in the half-cell for water electrolysis enhance the reaction rate,but typically also lower the stability.F or this reason, we used adiluted aqueous solution of KHCO 3 ,j ust necessary to have enough conductivity.The half-cell, in which ammonia is synthetized, operates with ac ontinuous flow of the reactants.T his cell scheme allows an easy recovery of ammonia from the gas stream leaving the cell.…”

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confidence: 99%

Electrocatalytic Synthesis of Ammonia at Room Temperature and Atmospheric Pressure from Water and Nitrogen on a Carbon‐Nanotube‐Based Electrocatalyst

et al. 2017

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Ammonia is synthesized directly from water and N at room temperature and atmospheric pressure in a flow electrochemical cell operating in gas phase (half-cell for the NH synthesis). Iron supported on carbon nanotubes (CNTs) was used as the electrocatalyst in this half-cell. A rate of ammonia formation of 2.2×10 gNH3 m h was obtained at room temperature and atmospheric pressure in a flow of N , with stable behavior for at least 60 h of reaction, under an applied potential of -2.0 V. This value is higher than the rate of ammonia formation obtained using noble metals (Ru/C) under comparable reaction conditions. Furthermore, hydrogen gas with a total Faraday efficiency as high as 95.1 % was obtained. Data also indicate that the active sites in NH electrocatalytic synthesis may be associated to specific carbon sites formed at the interface between iron particles and CNT and able to activate N , making it more reactive towards hydrogenation.

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“…In addition, there is the question of microfluidodynamics inside a porous semiconductor, with generation of gas bubbles (H 2 or O 2 ) and presence of a charged surface, with perhaps a not homogeneous surface charge distribution and a liquid (electrolyte) flowing tangential to the surface in pseudo-laminar flow. Other questions regards of how identify the optimal thickness in a nanostructured semiconductor [80], and of how realize an optimal combination between photocurrent generation and transport of protons to a proton-conductive membrane in photoelectrocatalytic devices with compact design [13,81].…”

Section: Technical Hurdlesmentioning

confidence: 99%

Chemical engineering role in the use of renewable energy and alternative carbon sources in chemical production

2019

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There is a demand for new chemical reaction technologies and associated engineering aspects due to on-going transition in energy and chemistry associated to moving out progressively from the use of fossil fuels. Focus is given in this review on two main aspects: i) the development of alternative carbon sources and ii) the integration of renewable energy in the chemical production. It is shown how addressing properly these aspects requires to develop also a) new tools for chemical engineering assessment and b) innovative methodologies for the development of the materials, reactors and processes. This review evidences the need to accelerate studies on these directions, being a crucial element to catalyze the transition to a more sustainable use of energy and chemistry. It is remarked, however, the need to go beyond the traditional approaches, with some examples given. In fact, the presence of radical changes in the way of production is underlined, requiring thus novel fundamentals and applied engineering approaches.

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Nanoscale Engineering in the Development of Photoelectrocatalytic Cells for Producing Solar Fuels

Cited by 26 publications

References 104 publications

Role of CuO in the modification of the photocatalytic water splitting behavior of TiO2 nanotube thin films

Role of CuO in the modification of the photocatalytic water splitting behavior of TiO2 nanotube thin films

Electrocatalytic Synthesis of Ammonia at Room Temperature and Atmospheric Pressure from Water and Nitrogen on a Carbon‐Nanotube‐Based Electrocatalyst

Chemical engineering role in the use of renewable energy and alternative carbon sources in chemical production

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