Scalable heating-up synthesis of monodisperse Cu2ZnSnS4 nanocrystals

Monodisperse Cu2ZnSnS4 (CZTS) nanocrystals (NCs), with quasi spherical shape, were prepared by a facile, high-yield, scalable, and high-concentration heat-up procedure. The key parameters to minimize the NC size distribution were efficient mixing and heat transfer in the reaction mixture through intensive argon bubbling and improved control of the heating ramp stability. Optimized synthetic conditions allowed the production of several grams of highly monodisperse CZTS NCs per batch, with up to 5 wt % concentration in a crude solution and a yield above 90%

Colloidal Ni2- : XCoxP nanocrystals for the hydrogen evolution reaction

A cost-effective and scalable approach was developed to produce monodisperse NiCoP nanocrystals (NCs) with composition tuned over the entire range (0 ≤ x ≤ 2). NiCoP NCs were synthesized using low-cost, stable and low-toxicity triphenyl phosphite (TPP) as a phosphorus source, metal chlorides as metal precursors and hexadecylamine (HDA) as a ligand. The synthesis involved the nucleation of amorphous Ni-P and its posterior crystallization and simultaneous incorporation of Co. The composition, size and morphology of the NiCoP NCs could be controlled simply by varying the ratio of Ni and Co precursors and the amounts of TPP and HDA. Ternary NiCoP-based electrocatalysts exhibited enhanced electrocatalytic activity toward the hydrogen evolution reaction (HER) compared to binary phosphides. In particular, NiCoP electrocatalysts displayed the lowest overpotential of 97 mV at J = 10 mA cm and an excellent long-term stability. DFT calculations of the Gibbs free energy for hydrogen adsorption at the surface of NiCoP NCs showed NiCoP to have the most appropriate composition to optimize this parameter within the whole NiCoP series. However, the hydrogen adsorption energy was demonstrated not to be the only parameter controlling the HER activity in NiCoP

Triphenyl phosphite as the phosphorus source for the scalable and cost-effective production of transition metal phosphides

Transition metal phosphides have great potential to optimize a number of functionalities in several energy conversion and storage applications, particularly when nanostructured or in nanoparticle form. However, the synthesis of transition metal phosphide nanoparticles and its scalability is often limited by the toxicity, air sensitivity, and high cost of the reagents used. We present here a simple, scalable, and cost-effective "heating up" procedure to produce metal phosphides using inexpensive, low-toxicity, and air-stable triphenyl phosphite as source of phosphorus and chlorides as metal precursors. This procedure allows the synthesis of a variety of phosphide nanoparticles, including phosphides of Ni, Co, and Cu. The use of carbonyl metal precursors further allowed the synthesis of FeP and MoP nanoparticles. The fact that minor modifications in the experimental parameters allowed producing nanoparticles with different compositions and even to tune their size and shape shows the high potential and versatility of the triphenyl phosphite precursor and the presented method. We also detail here a methodology to displace organic ligands from the surface of phosphide nanoparticles, which is a key step toward their application in energy conversion and storage systems

Synthesis, bottom up assembly and thermoelectric properties of Sb-doped PbS nanocrystal building blocks

The precise engineering of thermoelectric materials using nanocrystals as their building blocks has proven to be an excellent strategy to increase energy conversion efficiency. Here we present a synthetic route to produce Sb-doped PbS colloidal nanoparticles. These nanoparticles are then consolidated into nanocrystalline PbS:Sb using spark plasma sintering. We demonstrate that the introduction of Sb significantly influences the size, geometry, crystal lattice and especially the carrier concentration of PbS. The increase of charge carrier concentration achieved with the introduction of Sb translates into an increase of the electrical and thermal conductivities and a decrease of the Seebeck coefficient. Overall, PbS:Sb nanomaterial were characterized by two-fold higher thermoelectric figures of merit than undoped PbS

Cu_(2)ZnGeSe_(4) Nanocrystals: Synthesis and Thermoelectric Properties

A synthetic route for producing Cu_(2)ZnGeSe_(4) nanocrystals with narrow size distributions and controlled composition is presented. These nanocrystals were used to produce densely packed nanomaterials by hot-pressing. From the characterization of the thermoelectric properties of these nanomaterials, Cu_(2)ZnGeSe_(4) is demonstrated to show excellent thermoelectric properties. A very preliminary adjustment of the nanocrystal composition has already resulted in a figure of merit of up to 0.55 at 450 °C

Scalable heating-up synthesis of monodisperse Cu2ZnSnS4 nanocrystals

Monodisperse Cu2ZnSnS4 (CZTS) nanocrystals (NCs), with quasi-spherical shape, were prepared by a facile, high-yield, scalable, and high-concentration heat-up procedure. The key parameters to minimize the NC size distribution were efficient mixing and heat transfer in the reaction mixture through intensive argon bubbling and improved control of the heating ramp stability. Optimized synthetic conditions allowed the production of several grams of highly monodisperse CZTS NCs per batch, with up to 5 wt % concentration in a crude solution and a yield above 90%

J. Mater. Chem. A

We report on the photocatalytic hydrogen evolution under full-arc light irradiation of CuIn1-xGaxS2 wurtzite nanocrystals in the presence of SO32- and S2- as sacrificial reagents. We analyzed the hydrogen generation rate as a function of the Ga content and associated it with the energy band positions. For photocatalytic water splitting, the CuInS2 bandgap is slightly too low to efficiently overcome the reaction over-potential. The presence of Ga shifts up the CuInS2 conduction band edge providing a larger driving force for photogenerated carriers to activate the water splitting reduction reaction. The larger the Ga content, the more energetically favorable the electron injection, and thus a more efficient use of the photogenerated carriers is reached. However, the band gap increase associated with the Ga incorporation reduces the concentration of photogenerated carriers available for water splitting, and consequently a lower hydrogen conversion rate is obtained for very high Ga contents. The optimum Ga concentration was experimentally found at CuIn0.3Ga0.7S2.We report on the photocatalytic hydrogen evolution under full-arc light irradiation of CuIn1-xGaxS2 wurtzite nanocrystals in the presence of SO32- and S2- as sacrificial reagents. We analyzed the hydrogen generation rate as a function of the Ga content and associated it with the energy band positions. For photocatalytic water splitting, the CuInS2 bandgap is slightly too low to efficiently overcome the reaction over-potential. The presence of Ga shifts up the CuInS2 conduction band edge providing a larger driving force for photogenerated carriers to activate the water splitting reduction reaction. The larger the Ga content, the more energetically favorable the electron injection, and thus a more efficient use of the photogenerated carriers is reached. However, the band gap increase associated with the Ga incorporation reduces the concentration of photogenerated carriers available for water splitting, and consequently a lower hydrogen conversion rate is obtained for very high Ga contents. The optimum Ga concentration was experimentally found at CuIn0.3Ga0.7S2

Aqueous Room-Temperature Synthesis of Transition Metal Dichalcogenide Nanoparticles : A Sustainable Route to Efficient Hydrogen Evolution

Transition metal dichalcogenides (TMDs) have emerged as a focal point in electrocatalysis, particularly for the hydrogen evolution reaction (HER), owing to their notable catalytic activity, chemical stability, and cost-efficiency. Despite these advantages, the challenge of devising a practical and economical method for their large-scale application in HER remains an unresolved and critical issue. In this study, a facile, scalable, and cost-effective approach is introduced for producing high-yield, catalytically active TMD nanoparticles, including MoS, MoSe, RuS, and RuSe. These nanoparticles are synthesized through an aqueous room-temperature process, which is not only environmentally friendly but also economically feasible for large-scale production. Remarkably, these TMD nanoparticles exhibit versatile catalytic activity across a broad pH range for HER. Among them, RuSe nanoparticles demonstrate catalytic performance comparable to that of a commercial Pt/C electrode. Upon scaling up, the nanomaterials show great potential for integration into practical proton exchange membrane water electrolyzers, maintaining high efficiency even at large current densities and exhibiting very stable performance for up to 100 h. This research paves the way to a sustainable synthesis method of high-performance catalysts, tailored for industrial hydrogen production applications

J. Am. Chem. Soc.

Cu2ZnSnS4, based on abundant and environmental friendly elements and with a direct band gap of 1.5 eV, is a main candidate material for solar energy conversion through both photovoltaics and photocatalysis. We detail here the synthesis of quasi-spherical Cu2ZnSnS4 nanoparticles with unprecedented narrow size distributions. We further detail their use as seeds to produce CZTS-Au and CZTS-Pt heterostructured nanoparticles. Such heterostructured nanoparticles are shown to have excellent photocatalytic properties toward degradation of Rhodamine B and hydrogen generation by water splitting.Cu2ZnSnS4, based on abundant and environmental friendly elements and with a direct band gap of 1.5 eV, is a main candidate material for solar energy conversion through both photovoltaics and photocatalysis. We detail here the synthesis of quasi-spherical Cu2ZnSnS4 nanoparticles with unprecedented narrow size distributions. We further detail their use as seeds to produce CZTS-Au and CZTS-Pt heterostructured nanoparticles. Such heterostructured nanoparticles are shown to have excellent photocatalytic properties toward degradation of Rhodamine B and hydrogen generation by water splitting

Scalable heating-up synthesis of monodisperse Cu2ZnSnS4 nanocrystals

et al.Monodisperse CuZnSnS (CZTS) nanocrystals (NCs), with quasi-spherical shape, were prepared by a facile, high-yield, scalable, and high-concentration heat-up procedure. The key parameters to minimize the NC size distribution were efficient mixing and heat transfer in the reaction mixture through intensive argon bubbling and improved control of the heating ramp stability. Optimized synthetic conditions allowed the production of several grams of highly monodisperse CZTS NCs per batch, with up to 5 wt % concentration in a crude solution and a yield above 90%.This work was supported by the European Regional Development Funds and the Framework 7 program under the projects UNION (FP7-NMP-2012-310250), SCALENANO (FP7-NMP-ENERGY-2011-284486) and KESTCELLS (FP7/2007- 2013/316488) and the Spanish MINECO Project BOOSTER (ENE2013-46624-C4-3-R). M.I. thanks AGAUR for their Beatriu de Pinós postdoctoral grant (2013 BP-A00344). J.D.R. thanks the FWO (Research Foundation Flanders) for financial support. M.V.K. acknowledges partial financial supportby the European Union (EU) via FP7 ERC Starting Grant 2012 (Project NANOSOLID, GA No. 306733). Authors also acknowledge the funding from Generalitat de Catalunya 2014 SGR 1638.Peer Reviewe