Virgil Andrei

University of Cambridge | Cam · Department of Chemistry

The photoelectrochemical (PEC) production of syngas from water and CO2 represents an attractive technology towards a circular carbon economy. However, the high overpotential, low selectivity and cost of commonly employed catalysts pose challenges for this sustainable energy-conversion process. Here we demonstrate highly tunable PEC syngas productio...

Solar fuel production provides a sustainable route towards simultaneous energy harvesting and storage. However, this technology is hampered by the complexity and slow manual screening of the chemical design space to find suitable catalytic and light-harvesting materials. One solution is offered by automation, which has begun changing the landscape...

Photoelectrochemical (PEC) devices have been developed for direct solar fuel production but the limited stability of submerged light absorbers can hamper their commercial prospects.1,2 Here, we demonstrate photocathodes with an operational H2 evolution activity over weeks, by integrating a BiOI light absorber into a robust, oxide-based architecture...

While the field of thermoelectricity continues developing, the academic world is still debating its applicability for wide-scale implementation. The main concerns revolve around its low energy conversion efficiency (5-10%), compared to photovoltaics (upto 46%), and the environmental impact of commonly used materials (e.g. Bi2Te3, PbTe). Although le...

Photoelectrochemical (PEC) artificial leaves hold the potential to lower the costs of sustainable solar fuel production by integrating light harvesting and catalysis within one compact device. However, current deposition techniques limit their scalability1, whereas fragile and heavy bulk materials can affect their transport and deployment. Here we...

Integration of carbon capture with utilization technologies can lead the way to a net-zero carbon economy. Nevertheless, direct chemical conversion of captured CO2 products remains challenging due to their thermodynamic stability. Here, we demonstrate CO2 capture from flue gas/air and its direct conversion into syngas under solar irradiation withou...

Artificial photosynthesis can provide a solution to our current energy needs by converting small molecules such as water or carbon dioxide into useful fuels. This can be accomplished using photochemical diodes, which interface two complementary light absorbers with suitable electrocatalysts. Nanowire semiconductors provide unique advantages in term...

Solar-driven conversion of CO2 and plastics into value-added products provides a potential sustainable route towards a circular economy, but their simultaneous conversion in an integrated process is challenging. Here we introduce a versatile photoelectrochemical platform for CO2 conversion that is coupled to the reforming of plastic. The perovskite...

ConspectusThe sustainable synthesis of fuels and chemicals is key to attaining a carbon-neutral economy. This can be achieved by mimicking the light-harvesting and catalytic processes occurring in plants. Solar fuel production is commonly performed via established approaches, including photovoltaic-electrochemical (PV-EC), photoelectrochemical (PEC...

The production of clean fuels and chemicals from waste feedstocks is an appealing approach towards creating a circular economy. However, waste photoreforming commonly employs particulate photocatalysts, which display low product yields, selectivity, and reusability. Here, a perovskite‐based photoelectrochemical (PEC) device is reported, which produ...

Biomass Transformation In article number 2109313, Erwin Reisner and co‐workers introduce a bias‐free thin‐film device, which can reform diverse waste streams, including biomass, industrial by‐products, and plastic waste, into value‐added chemicals and clean H2 fuel using sunlight. The versatile prototype demonstrates the potential of photoelectroch...

In der semi‐artifiziellen Photoelektrochemie werden Halbleiter mit Biokatalysatoren für die selektive chemische Synthese mittels Sonnenlicht kombiniert, aber die Gesamtenergieumwandlungseffizienz dieser Hybridsysteme war bisher begrenzt. In ihrer Zuschrift (DOI: 10.1002/ange.202110867) berichten Erwin Reisner et al. über die Kontrolle der lokalen U...

Semi‐artificial photoelectrochemistry combines semiconductors with biocatalysts for selective chemical synthesis powered by sunlight, but the overall energy conversion efficiency of these hybrid systems remained limited to date. In their Communication (DOI: 10.1002/anie.202110867), Erwin Reisner et al. report the control of the local environment of...

Semi‐artificial photoelectrochemistry can combine state‐of‐the‐art photovoltaic light‐absorbers with enzymes evolved for selective fuel‐forming reactions such as CO2 reduction, but the overall performance of such hybrid systems has been limited to date. Here, control of the local environment via the electrolyte solution has been applied to facilita...

Semi‐artificial photoelectrochemistry can combine state‐of‐the‐art photovoltaic light‐absorbers with enzymes evolved for selective fuel‐forming reactions such as CO2 reduction, but the overall performance of such hybrid systems has been limited to date. Here, control of the local environment via the electrolyte solution has been applied to facilita...

Photoelectrochemical (PEC) fuel synthesis depends on the intermittent solar intensity of the diurnal cycle and ceases at night. Here, an integrated device that does not only possess PEC water splitting functionality, but also operates as an electrolyzer in the nocturnal period to improve the overall capacity factor is described. The bifunctional sy...

Photoelectrocatalysis can directly store solar energy in chemical fuels like hydrogen, but its performance relies on external factors (such as light intensity and weather). In article number 2008182, Erwin Reisner and co‐workers report a hybrid perovskite‐BiVO4 device that can perform light‐driven water splitting during daytime and switch to water...

Harvesting solar energy to convert CO2 into chemical fuels is a promising technology to curtail the growing atmospheric CO2 levels and alleviate the global dependence on fossil fuels; however, the assembly of efficient and robust systems for the selective photoconversion of CO2 without sacrificial reagents and external bias remains a challenge. Her...

Sunlight-driven production of fuels is attracting attention for the generation of storable renewable energy, but the design of selective catalysts for CO2 utilization and the assembly of unassisted devices for selective and efficient CO2-to-fuel conversion remains challenging. In this study, we report a bimetallic Cu96In4 alloy with a dendritic foa...

The development of thin-film thermoelectric applications in sensing and energy harvesting can benefit largely from suitable deposition methods for earth-abundant materials. In this study, p-type copper oxide thin films have been prepared on soda lime silicate glass by direct current (DC) magnetron sputtering at room temperature from a pure copper m...

Perovskite solar cells are notoriously moisture-sensitive, but recent encapsulation strategies have demonstrated their potential application as photoelectrodes in aqueous solution. However, perovskite photoelectrodes rely on precious metal co-catalysts and their combination with biological materials remains elusive. Here, we interface [NiFeSe] hydr...

Metal halide perovskites are actively pursued as photoelectrodes to drive solar fuel synthesis. However, currently these photocathodes suffer from a limited stability in water, which hampers their practical application. Here we report a high-performance solution-processable photocathode composed of cesium formamidinium methylammonium (CsFAMA) tripl...

Lu_et_al-2018-Advanced_Materials.sup-1.pdf

jp7b12464_si_001.pdf

Andrei_et_al-2018-Advanced_Energy_Materials.sup-1.pdf

Single-source precursors are used to produce nanostructured BiVO4 photoanodes for water oxidation in a straightforward and scalable drop-casting synthetic process. Polyoxometallate precursors, which contain both Bi and V, are produced in a one-step reaction from commercially available starting materials. Simple annealing of the molecular precursor...

Strong interest exists in the development of organic–inorganic lead halide perovskite photovoltaics and of photoelectrochemical (PEC) tandem absorber systems for solar fuel production. However, their scalability and durability have long been limiting factors. In this work, it is revealed how both fields can be seamlessly merged together, to obtain...

As the most abundant natural polymer, cellulose presents a unique advantage for large‐scale applications. To fully unlock its potential, the introduction of desired functional groups onto the cellulose backbone is required, which can be realized by either chemical bonding or physical surface interactions. This review gives an overview of the chemis...

Hydrogenases (H2ases) are benchmark electrocatalysts in H2 production, both in biology and (photo)catalysis in vitro. We report the tailoring of a p‐type Si photocathode for optimal loading and wiring of H2ase by the introduction of a hierarchical inverse opal (IO) TiO2 interlayer. This proton reducing Si|IO‐TiO2|H2ase photocathode is capable of dr...

Hydrogenases (H2ases) are benchmark electrocatalysts in H2 production, both in biology and (photo)catalysis in vitro. We report the tailoring of a p‐type Si photocathode for optimal loading and wiring of H2ase by the introduction of a hierarchical inverse opal (IO) TiO2 interlayer. This proton reducing Si|IO‐TiO2|H2ase photocathode is capable of dr...

A trend in high performing lead halide perovskite solar cell devices has been increasing compositional complexity by successively introducing more elements, dopants, and additives into the structure; and some of the latest top efficiencies have been achieved with a quadruple cation mixed halide perovskite CsxFAyMAzRb1-x-y-zPbBrqI3-q. This paper con...

Although the deposition of alternating layers from poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) and polyaniline (PANI) salts has recently provided a breakthrough in the field of conductive polymers, the cause for the conductivity enhancement has remained unclear. In this work, we report a cooperative doping effect between al...

This work reveals that the electrical conductivity σ of a poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) film can be significantly increased by spin-coating multiple thin layers onto a substrate. Generally, σ can be improved by more than fourfold for multiple layers, as compared to a single thicker one. A gradual enhancement is...

As thermoelectric devices begin to make their way into commercial applications, the emphasis is put on decreasing the thermal conductivity. In this purely theoretical study, finite element analysis is used to determine the effect of a supporting material on the thermal conductivity of a thermoelectric module. The simulations illustrate the heat tra...

Time dependence of the temperature profile for a supported PbTe layer. The view is magnified along the direction of the temperature gradient. The front face of the Pyrex substrate is heated at a constant temperature of 393 K. (PDF)

Full-scale comparison of a 100 nm thin film with a 1 mm thick layer, both supported on a glass slide. The temperature is kept constant at the front face of the Pyrex glass (PG) for: (a) Cu, (b) Cu2O, (c) PbTe. The heat flux is maintained constant at the front face of the Pyrex glass for: (d) Cu, (e) Cu2O, (f) PbTe. (PDF)

Temperature distribution within the microscope slide. The Pyrex glass (PG) is either heated at one end at a constant temperature of 393 K (marked with T in the sample name), or at a constant heat flux of 105 W m−2 (marked with E): (a) enlarged view, (b) full-scale view. (PDF)

Thermal properties for the Pyrex glass. The thermal conductivity (κ) is depicted in black and the heat capacity at constant pressure (CP) in red. (PDF)

Full-scale comparison of a free standing 1 mm thick layer and a 1 mm layer on a microscope slide. The temperature is kept constant at the front face of the Pyrex glass (PG) for: (a) Cu, (b) Cu2O, (c) PbTe. The heat flux is maintained constant at the front face of the Pyrex glass for: (d) Cu, (e) Cu2O, (f) PbTe. (PDF)

Time dependence of the temperature distribution along the upper surface of the supported PbTe layers. The generated temperature profiles are shown once every second, for the full simulated time range of 1-40 s. The front face of the Pyrex glass is heated at a constant temperature of 393 K in the frames (a) and (b), corresponding to Fig 3(c) from th...

Fitted functions for different properties of the investigated materials, as taken from Comsol Multiphysics. (PDF)

Mathematical deduction of the effective thermal conductivity obtained from the 1D model of thermal resistances in parallel. (PDF)

Model of our investigated system, for illustrating the different possible types of heat transfer. The thermal resistances of the layers are arranged in parallel (similar to our investigations) or in series, according to the direction of the heat flow Q˙. yglass represents the length of the layers, A is their heated area and κ the thermal conductivi...

We present a facile alternative to other well known strategies for synthesizing flexible thermoelectric materials. Instead of printing thin active layers on flexible substrates or doping conductive polymers, we produce thermoelectric pastes, using a mixture of graphite, copper(I) oxide and polychlorotrifluoroethene. The Seebeck coefficient of the i...

Copper(I) oxide based compounds are investigated as earth abundant, environmentally friendly thermoelectric materials. Copper(I) oxide powders from different vendors are first examined, resulting in Seebeck coefficients of approximately 650lV/K. Pastes of the powders with two different polymer matrices, polychlorotrifluoroethene and polydimethylsil...