Earth-Abundant Tin Sulfide-Based Photocathodes for Solar Hydrogen Production.

Tin-based chalcogenide semiconductors, though attractive materials for photovoltaics, have to date exhibited poor performance and stability for photoelectrochemical applications. Here, a novel strategy is reported to improve performance and stability of tin monosulfide (SnS) nanoplatelet thin films for H2 production in acidic media without any use of sacrificial reagent. P-type SnS nanoplatelet films are coated with the n-CdS buffer layer and the TiO2 passivation layer to form type II heterojunction photocathodes. These photocathodes with subsequent deposition of Pt nanoparticles generate a photovoltage of 300 mV and a photocurrent density of 2.4 mA cm-2 at 0 V versus reversible hydrogen electrode (RHE) for water splitting under simulated visible-light illumination (λ > 500 nm, Pin = 80 mW cm-2). The incident photon-to-current efficiency at 0 V versus RHE for H2 production reach a maximum of 12.7% at 575 nm with internal quantum efficiency of 13.8%. The faradaic efficiency for hydrogen evolution remains close to unity after 6000 s of illumination, confirming the robustness of the heterojunction for solar H2 production

Organic solvent free PbI₂ recycling from perovskite solar cells using hot water

Perovskite solar cells represent an emerging and highly promising renewable energy technology. However, the most efficient perovskite solar cells critically depend on the use of lead. This represents a possible environmental concern potentially limiting the technologiesâEurotm commercialization. Here, we demonstrate a facile recycling process for PbI2, the most common lead-based precursor in perovskite absorber material. The process uses only hot water to effectively extract lead from synthetic precursor mixes, plastic- and glass-based perovskites (92.6 âEuro" 10

Synthesis and Characterization of High-Photoactivity Electrodeposited Cu2O solar absorber by photoelectrochemistry and ultrafast spectroscopy

We present a systematic study on the effects of electrodeposition parameters on the photoelectrochemical properties of Cu2O. The influence of deposition variables (temperature, pH, and deposition current density) on conductivity has been widely explored in the past for this semiconductor, but the optimization of the electrodeposition process for the photoelectrochemical response in aqueous solutions under AM 1.5 illumination has received far less attention. In this work, we analyze the photoactivity of Cu2O films deposited at different conditions and correlate the photoresponse to morphology, film orientation, and electrical properties. The photoelectrochemical response was measured by linear sweep voltammetry under chopped simulated AM 1.5 illumination. The highest photocurrent obtained was −2.4 mA cm−2 at 0.25 V vs RHE for a film thickness of 1.3 μm. This is the highest reported value reached so far for this material in an aqueous electrolyte under AM 1.5 illumination. The optical and electrical properties of the most photoactive electrode were investigated by UV−vis spectroscopy and electrochemical impedance, while the minority carrier lifetime and diffusion length were measured by optical-pump THz-probe spectroscopy

Benchmark performance of low-cost Sb2Se3 photocathodes for unassisted solar overall water splitting

Determining cost-effective semiconductors exhibiting desirable properties for commercial photoelectrochemical water splitting remains a challenge. Herein, we report a Sb2Se3 semiconductor that satisfies most requirements for an ideal high-performance photoelectrode, including a small band gap and favourable cost, optoelectronic properties, processability, and photocorrosion stability. Strong anisotropy, a major issue for Sb2Se3, is resolved by suppressing growth kinetics via close space sublimation to obtain high-quality compact thin films with favourable crystallographic orientation. The Sb2Se3 photocathode exhibits a high photocurrent density of almost 30mAcm(-2) at 0V against the reversible hydrogen electrode, the highest value so far. We demonstrate unassisted solar overall water splitting by combining the optimised Sb2Se3 photocathode with a BiVO4 photoanode, achieving a solar-to-hydrogen efficiency of 1.5% with stability over 10h under simulated 1 sun conditions employing a broad range of solar fluxes. Low-cost Sb2Se3 can thus be an attractive breakthrough material for commercial solar fuel production. While photoelectrochemical water splitting offers an integrated means to convert sunlight to a renewable fuel, cost-effective light-absorbers are rare. Here, authors report Sb2Se3 photocathodes for high-performance photoelectrochemical water splitting devices

Photoelectrochemical H2 Evolution with a Hydrogenase Immobilized on a TiO2-Protected Silicon Electrode.

The combination of enzymes with semiconductors enables the photoelectrochemical characterization of electron-transfer processes at highly active and well-defined catalytic sites on a light-harvesting electrode surface. Herein, we report the integration of a hydrogenase on a TiO2-coated p-Si photocathode for the photo-reduction of protons to H2. The immobilized hydrogenase exhibits activity on Si attributable to a bifunctional TiO2 layer, which protects the Si electrode from oxidation and acts as a biocompatible support layer for the productive adsorption of the enzyme. The p-Si|TiO2|hydrogenase photocathode displays visible-light driven production of H2 at an energy-storing, positive electrochemical potential and an essentially quantitative faradaic efficiency. We have thus established a widely applicable platform to wire redox enzymes in an active configuration on a p-type semiconductor photocathode through the engineering of the enzyme-materials interface

Oriented 2.0.0 Cu2O nanoplatelets supported on few-layers graphene as efficient visible light photocatalyst for overall water splitting

[EN] Cu2O nanoplatelets with preferential 2.0.0 facet orientation supported on few layers graphene were prepared as films in a single step by pyrolysis at 900 degrees C under inert atmosphere of Cu2+-chitosan precursor. (Cu2O) over bar /fl-G films exhibit a photocatalytic activity for overall water splitting of 19.5 mmol/g(cu+G) h. This value is about 4 orders of magnitude higher than the photocatalytic activity measured for unoriented Cu2O nanoparticles on few-layers graphene or than commercial Cu2O nanoparticles and about three orders of magnitude higher than the activity reported in the literature for Cu2O nanoparticles. In addition Cu2O nanoparticles on few-layers graphene retain about 50% of its photocatalytic activity after 6 days of continuous irradiation. It is proposed that this activity and stability arises from the combination of features derived from the pyrolysis preparation procedure including strong Cu2O-graphene grafting, the role of graphene as cocatalyst and preferential 2.0.0 facet orientation. (C) 2016 Elsevier B.V. All rights reserved.Finantial support by the Spanish Ministry of Economy and Competitiveness (Severo Ochoa and CTQ2015-69153-CO2-1-R) and Generalitat Valenciana (Prometeo 2013-019) is gratefully acknowledged. D. M. M. and I. E. A thank to the Technical University of Valencia and the Spanish Ministry of Science for PhD scholarshipsMateo-Mateo, D.; Esteve-Adell, I.; Albero-Sancho, J.; Primo Arnau, AM.; García Gómez, H. (2017). Oriented 2.0.0 Cu2O nanoplatelets supported on few-layers graphene as efficient visible light photocatalyst for overall water splitting. Applied Catalysis B Environmental. 201:582-590. https://doi.org/10.1016/j.apcatb.2016.08.033S58259020

Synthetic strategies to nanostructured photocatalysts for CO2 reduction to solar fuels and chemicals

Artificial photosynthesis represents one of the great scientific challenges of the 21st century, offering the possibility of clean energy through water photolysis and renewable chemicals through CO2 utilisation as a sustainable feedstock. Catalysis will undoubtedly play a key role in delivering technologies able to meet these goals, mediating solar energy via excited generate charge carriers to selectively activate molecular bonds under ambient conditions. This review describes recent synthetic approaches adopted to engineer nanostructured photocatalytic materials for efficient light harnessing, charge separation and the photoreduction of CO2 to higher hydrocarbons such as methane, methanol and even olefins