[Due to the increasing size of the archives, each topic page now contains only the prior 365 days of content. Access to older stories is now solely through the Monthly Archive pages or the site search function.]
Berkeley team develops host-guest nanowires for efficient water splitting and solar energy storage
February 04, 2016
Although metal oxides that absorb visible light are attractive for use as photoanodes in photoelectrosynthetic cells, their performance is often limited by poor charge carrier transport. Researchers from UC Berkeley and colleagues have now addressed this issue by using separate materials for light absorption and carrier transport.
The team reports on their host-guest system of Ta:TiO2|BiVO4 as a photoanode for use in solar water splitting cells in an open-access paper in the journal ACS Central Science. BiVO4 acts as a visible light-absorber and Ta:TiO2 acts as a high surface area electron conductor. The host–guest nanowire architecture allows for simultaneously high light absorption and carrier collection efficiency for efficient solar water oxidation.
Berkeley Lab team creates “cyborgian” hybrid artificial photosynthesis system; CO2 to acetic acid at high yield
January 05, 2016
Researchers at Berkeley Lab have induced the self-photosensitization of a nonphotosynthetic bacterium—Moorella thermoacetica—with cadmium sulfide nanoparticles (M. thermoacetica–CdS), enabling the photosynthesis of acetic acid from carbon dioxide.
Their hybrid approach combines the highly efficient light harvesting of inorganic semiconductors with the high specificity, low cost, and self-replication and -repair of biocatalysts. Biologically precipitated cadmium sulfide nanoparticles served as the light harvester to sustain cellular metabolism. This self-augmented biological system selectively produced acetic acid continuously over several days of light-dark cycles at relatively high quantum yields, demonstrating a self-replicating route toward solar-to-chemical CO2 reduction. A paper on their work is published in Science.
Bauhaus Luftfahrt analysis finds solar thermochemical jet fuel production viable only if CO2 captured from renewable sources and not flue gases
December 23, 2015
A team from Bauhaus Luftfahrt in Germany has analyzed the climate impact and economic performance of solar thermochemical jet fuel production. According to their analysis, published in the ACS journal Environmental Science & Technology, favorable assumptions for all involved process steps (30% thermochemical energy conversion efficiency; 3000 kWh/(m2 a) solar irradiation, low CO2 and heliostat costs) result in jet fuel production costs of €1.28/L (US$5.30/gallon) at lifecycle (LC) GHG emissions close to zero (0.10 kgCO2‐equiv/L.
The non-profit Bauhaus Luftfahrt is an internationally-oriented think tank created in November 2005 by the three aerospace companies EADS (today Airbus Group); Liebherr-Aerospace; and MTU Aero Engines as well as the Bavarian Ministry for Economic Affairs. In January 2012, IABG-Industrieanlagen-Betriebsgesellschaft became the latest member of the institution.
USPTO awards patent to UMD team for process to make gasoline through fermentation; electrofuels
December 22, 2015
The US Patent and Trademark Office issued patent Nº 9,217,161 for a process using naturally occurring microorganisms to ferment biomass or gases directly to hydrocarbons such as hexane and octane. The fuels separate and rise to the surface of the fermentation broth, and are exactly the same as current components of gasoline.
The inventors are Professor Richard Kohn and Faculty Research Associate Dr. Seon-Woo Kim from the University of Maryland (UMD). The team was awarded a separate patent earlier this year (9,193,979) for ethanol-tolerant microorganisms that convert cellulosic biomass to ethanol. (Earlier post.) Both processes were developed based on their theory, described in in a paper published in the Journal of Theoretical Biology, that fermentation systems drive toward thermodynamic equilibrium.
NREL research advances photoelectrochemical production of hydrogen using molecular catalyst
December 21, 2015
Researchers at the Energy Department’s National Renewable Energy Laboratory (NREL) have made advances toward affordable photoelectrochemical (PEC) production of hydrogen. A paper on their work is published in Nature Materials.
The PEC process uses solar energy to split water into hydrogen and oxygen. The process requires special semiconductors, the PEC materials and catalysts to split the water. Previous work used precious metals such as platinum, ruthenium and iridium as catalysts attached to the semiconductors. A large-scale commercial effort using those precious metals wouldn’t be cost-effective, however.
Purdue, EPFL team propose Hydricity concept for integrated co-production of H2 and electricity from solar thermal energy
December 16, 2015
Researchers from Purdue University and École Polytechnique Fédérale de Lausanne (EPFL) in Switzerland are proposing a new integrated process involving the co-production of hydrogen and electricity from solar thermal energy—a concept they label “hydricity”. They describe their proposal in a paper in the Proceedings of the National Academy of Sciences (PNAS).
The hydricity process entails integrating solar water power (SWP) cycle and solar thermal hydrogen production technologies and a turbine-based hydrogen power cycle with suitable improvements of each for compatibility and beneficial interaction.
Stanford team increases power of corrosion-resistant solar cells; advance for solar fuels
November 30, 2015
Researchers at Stanford, with colleagues at University College Cork in Ireland, have shown how to increase the power of corrosion-resistant solar cells, setting a record for solar energy output under water. Instead of pumping electricity into the grid, the power these cells produce would be used in the production of solar fuels.
This new work, published in Nature Materials, was led by Stanford materials scientist Paul McIntyre, whose lab has been a pioneer in the field of artificial photosynthesis. Artificial photosynthesis proposes using the energy from specialized solar cells to combine water with captured carbon dioxide to produce industrial fuels.
Joule and Red Rock Biofuels intend to merge; solar fuels plus biomass F-T
November 12, 2015
Joule, a pioneer in producing liquid fuels from recycled CO2, and Red Rock Biofuels, a leading developer of renewable jet and diesel fuel bio-refineries using the Fischer-Tropsch process, announced that they intend to merge. Red Rock adds a proven technology pathway to Joule’s own Helioculture technology and strengthens Joule’s platform for global supply of carbon neutral fuels, the two said. The transaction is expected to close during the coming 30 days.
In association with this merger, Joule also announced that President and CEO Serge Tchuruk, will return to his previous board role. Dr. Brian Baynes, a current board member of both Joule and Red Rock and partner at Flagship Ventures, will succeed Tchuruk and will lead Joule as it enters a commercial deployment phase.
JCAP researchers propose artificial photosynthetic system for high-yield production of ethanol
November 09, 2015
A team at the Joint Center for Artificial Photosynthesis (JCAP) at Lawrence Berkeley National Laboratory and UC Berkeley is proposing an artificial photosynthesis scheme for direct synthesis and separation to almost pure ethanol with minimum product crossover using saturated salt electrolytes.
In a paper in the RSC journal Energy & Environmental Science, Professor Alexis Bell and postdoc Meenesh Singh describe the novel design of an integrated artificial photosynthetic system that continuously produces >90 wt% pure ethanol using a polycrystalline copper cathode and an IrO2 anode at a current density of 0.85 mA cm-2. The annual production rate of > 90 wt% ethanol using such a photosynthesis system operating at 10 mA cm-2 (12% solar-to-fuel (STF) efficiency) can be 15.27 million gallons per year per square kilometer, corresponding to 7% of the industrial ethanol production capacity of California, they suggest.
Sandia team boosts hydrogen production activity by molybdenum disulfide four-fold; low-cost catalyst for solar-driven water splitting
October 07, 2015
A team led by researchers from Sandia National Laboratories has shown that molybdenum disulfide (MoS2), exfoliated with lithiation intercalation to change its physical structure, performs as well as the best state-of-the-art catalysts for the hydrogen evolution reaction (HER) but at a significantly lower cost. An open access paper on their study is published in the journal Nature Communications.
The improved catalyst has already released four times the amount of hydrogen ever produced by MoS2 from water. To Sandia postdoctoral fellow and lead author Stan Chou, this is just the beginning: “We should get far more output as we learn to better integrate molly with, for example, fuel-cell systems,” he said.
Rice team demonstrates plasmonic hot-electron solar water-splitting technology; simpler, cheaper and efficient
September 05, 2015
Researchers at Rice have demonstrated an efficient new way to use solar energy for water splitting. The technology, described in a paper in the ACS journal Nano Letters, relies on a novel plasmonic photoelectrode architecture of light-activated gold nanoparticles that harvest sunlight to drive photocatalytic reactions by efficient, non-radiative plasmon decay into “hot carriers”—highly excited electrons.
In contrast to past work, the new architecture does not utilize a Schottky junction—the commonly used building block to collect hot carriers. Instead, the team observed large photocurrents from a Schottky-free junction due to direct hot electron injection from plasmonic gold nanoparticles into the reactant species upon plasmon decay.
JCAP team reports first complete “artificial leaf”; >10% solar-to-hydrogen conversion efficiency
August 28, 2015
Researchers at the Joint Center for Artificial Photosynthesis (JCAP) report the development of the first complete, efficient, safe, integrated solar-driven system—an “artificial leaf”—for splitting water to produce hydrogen. JCAP is a US Department of Energy (DOE) Energy Innovation Hub established at Caltech and its partnering institutions in 2010.
The new system has three main components: two electrodes—one photoanode and one photocathode—and a membrane. The photoanode uses sunlight to oxidize water molecules, generating protons and electrons as well as oxygen gas. The photocathode recombines the protons and electrons to form hydrogen gas. A key part of the JCAP design is the plastic membrane, which keeps the oxygen and hydrogen gases separate. If the two gases are allowed to mix and are accidentally ignited, an explosion can occur; the membrane lets the hydrogen fuel be separately collected under pressure and safely pushed into a pipeline.
Berkeley Lab researchers advance hybrid bioinorganic approach to solar-to~chemicals conversion; 50% electrical-to-chemical, 10% solar-to-chemical efficiencies
August 25, 2015
A team of researchers at the US Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) have hit a new milestone in their development of a hybrid bioinorganic system for solar-to-chemical energy conversion. (Earlier post.) The system first generates renewable hydrogen from water splitting using sustainable electrical and/or solar input and biocompatible inorganic catalysts. The hydrogen is then used by living cells as a source of reducing equivalents for conversion of CO2 to the value-added chemical product methane.
The system can achieve an electrical-to-chemical efficiency of better than 50% and a solar-to-chemical energy conversion efficiency of 10% if the system is coupled with state-of-art solar panel and electrolyzer, said Peidong Yang, a chemist with Berkeley Lab’s Materials Sciences Division and one of the leaders of this study. A paper on their work is published in Proceedings of the National Academy of Sciences (PNAS).
Volkswagen AG coordinating new €6M EU research project on drop-in biocatalytic solar fuels
June 26, 2015
Volkswagen AG is coordinating a new €6-million (US$6.7-million) research project, selected for funding under the Horizon 2020 Programme, to advance the biocatalytic production of drop-in liquid hydrocarbon transportation fuels, requiring only sunlight, CO2 and water.
The basic approach of the new 4-year Photofuel project is to develop and to advance microbes (the biocatalysts) that will directly excrete hydrocarbon and long-chain alcohol fuel compounds to the growth medium, from which the fuels are separated, without the need to harvest biomass. This basic concept is in line with the fundamental approach (CO2 + water + renewable energy → drop-in fuels) being taken by Audi (a member of the Volkswagen Group) in its e-fuels initiatives. (Earlier post.)
Joule issued patent on production of medium chain-length alkanes from sunlight and CO2; diesel, jet fuel and gasoline
June 16, 2015
Joule, the developer of engineered photosynthetic bacteria as catalysts for the direct production of targeted fuel molecules in a continuous, single-step conversion process, announced the issuance of an additional patent, extending its ability to target the highest-value molecules of the petroleum distillation process and generate them on demand from sunlight and CO2.
US Patent Nº 9,034,629, issued on 19 May, covers both the cyanobacterium and the process for directly converting CO2 into medium chain-length alkanes (C7-11), which are in the diesel, jet fuel and gasoline ranges.
“Energiewende” in a tank; Audi e-fuels targeting carbon-neutral driving with synthetic fuels from renewables, H2O and CO2; Swiss policy test case
June 12, 2015
Like other major automakers, Audi (and its parent Volkswagen Group) is working on meeting its medium-term regulatory requirements (e.g., in the 2020 timeframe) by reducing the average fuel consumption of its new vehicles using a combination of three primary measures: optimizing its combustion engines for greater efficiency; developing alternative drive concepts, such as hybrid, plug-in hybrid and gas-powered vehicles; and reducing total vehicle weight through lightweight construction with an intelligent multimaterial mix.
Unlike the others, however, Audi over the past few years has embarked on a comprehensive approach to developing a range of new CO₂-neutral fuels as part of its overall strategy for sustainable, carbon-neutral mobility: Audi e-fuels. Audi’s basic goal is to combine renewable energy (e.g. solar and wind), water and CO2 to produce liquid or gaseous fuels with a very low carbon intensity. Audi e-fuels are intended to use no fossil or biomass sources; do not compete with food production; and are 100% compatible with existing infrastructure.
Delivery of renewable isooctane to Audi tips interesting potential non-biomass pathway for biogasoline; “e-benzin” as solar fuel
May 26, 2015
Last week, Audi and its partner Global Bioenergies announced that the first batch of renewable isooctane—which Audi calls “e-benzin”—using Global Bioenergies’ fermentative isobutene pathway (sugar→isobutene→isooctane) had been produced and presented to Audi by Global Bioenergies. (Earlier post.)
Global Bioenergies, founded in 2008, has developed a synthetic isobutene pathway that, when implanted in a micro-organism, enables the organism to convert sugars (e.g., from starch and biomass) via fermentation into gaseous isobutene via a several-stage enzymatic process. However, following the delivery of the first renewable isooctane, Reiner Mangold, Audi’s head of sustainable product development, said that Audi was “now looking forward to working together with Global Bioenergies on a technology allowing the production of renewable isooctane not derived from biomass sources”—i.e., using just water, H2, CO2 and sunlight.
Audi partner Joule announces its “CO2-recycled” ethanol meets US and Euro specs; $40M financing
May 11, 2015
Joule, the developer of a direct, single-step, continuous process for the production of solar hydrocarbon fuels using engineered cyanobacteria (earlier post), announced the successful results from third-party testing of its ethanol fuel (Sunflow-E), setting the stage to obtain certification for commercial use.
Initiated by Audi, Joule’s strategic partner in the automotive space (earlier post), the test results confirm that Joule’s ethanol meets: American Society for Testing and Materials (ASTM) D4806 – Denatured fuel ethanol for blending with gasolines for use as automotive spark-ignition engine fuel; and German Institute for Standardization (DIN) EN 15376 – Ethanol as a blending component for petrol.
DOE to re-fund Joint Center for Artificial Photosynthesis with $75M for solar fuels R&D
April 29, 2015
The US Department of Energy announced $75 million in funding to renew the Joint Center for Artificial Photosynthesis (JCAP), a DOE Energy Innovation Hub originally established in 2010 with the goal of harnessing solar energy for the production of fuel. (Earlier post.)
Under the renewal plan, the five-year-old center would receive funding for an additional five years of research, subject to Congressional appropriations. JCAP researchers are focused on achieving the major scientific breakthroughs needed to produce liquid transportation fuels from a combination of sunlight, water, and carbon dioxide, using artificial photosynthesis.
SOLARJET demonstrates full process for thermochemical production of renewable jet fuel from H2O & CO2
April 28, 2015
The European consortium SOLARJET (Solar chemical reactor demonstration and Optimization for Long-term Availability of Renewable JET fuel) (earlier post) has experimentally demonstrated the entire process chain for the first production of renewable jet fuel via a thermochemical H2O/CO2-splitting cycle using simulated concentrated solar radiation.
The solar-to-fuel energy conversion efficiency was 1.72%, without sensible heat recovery. A total of 291 stable redox cycles were performed, yielding 700 standard liters of syngas of composition 33.7% H2, 19.2% CO, 30.5% CO2, 0.06% O2, 0.09% CH4, and 16.5% Ar, which was compressed to 150 bar and further processed via Fischer–Tropsch synthesis to a mixture of naphtha, gasoil, and kerosene. Their paper is published in the ACS journal Energy & Fuels.
Research facility in Dresden produces first batch of Audi e-diesel; sunfire’s power-to-liquid technology
April 21, 2015
A pilot plant in Dresden has started production of the synthetic fuel Audi e-diesel using water, CO2 and green power—i.e., power-to-liquid (PtL). After a commissioning phase of just four months, the research facility in Dresden started producing its first batches of high‑quality diesel fuel a few days ago. (Earlier post.)
The energy technology company sunfire is Audi’s project partner and the plant operator. The CO2 used is currently supplied by a biogas facility. In addition, initially a portion of the CO2 needed is extracted from the ambient air by means of direct air capturing, a technology of Audi’s Zurich‑based partner Climeworks.
University of Adelaide team exploring novel configuration for solar hybridized coal-to-liquids process
April 13, 2015
|Simplified flowsheet of the proposed solar hybridized coal- to-liquids (SCTL) process with the proposed solar hybridized dual fluidized bed (SDFB) gasifier. Credit: ACS, Guo et al. Click to enlarge.|
Researchers at the University of Adelaide (Australia) are proposing a novel configuration of a hybridized concentrated solar thermal (CST) dual fluidized bed (DFB) gasification process for Fischer–Tropsch liquids (FTL) fuels production. In their investigation of the process, reported in a paper in the ACS journal Energy & Fuels, they used lignite as the feedstock (Solar hybridized coal to liquids, SCTL), although the process could also be used with biomass.
Although fuel products produced via the Fischer-Tropsch process are high quality (free of sulfur, nitrogen and other contaminants found in petroleum-derived products), and coal is a plentiful and low-cost feedstock, the very high greenhouse gas emissions from coal-to-liquids production processes are a major barrier. As one approach to reducing the overall carbon intensity of FT fuels, there is growing interest in introducing concentrated solar power as a heat source into the gasification process.
UC Berkeley hybrid semiconductor nanowire-bacteria system for direct solar-powered production of chemicals from CO2 and water
April 10, 2015
Researchers at UC Berkeley have developed an artificial photosynthetic scheme for the direct solar-powered production of value-added chemicals from CO2 and water using a two-step process involving a biocompatible light-capturing nanowire array with a direct interface with microbial systems.
As a proof of principle, they demonstrated that, using only solar energy input, such a hybrid semiconductor nanowire–bacteria system can reduce CO2 at neutral pH to a wide array of chemical targets, such as fuels, polymers, and complex pharmaceutical precursors A paper on their work is published in the ACS journal Nano Letters.
UW-Madison team develops novel hydrogen-producing photoelectrochemical cell using solar-driven biomass conversion as anode reaction
March 11, 2015
Researchers at the University of Wisconsin-Madison have developed an innovative hydrogen-producing photoelectrochemical cell (PEC), using solar-driven biomass conversion as the anode reaction. In a paper in the journal Nature Chemistry, the duo reports obtaining a near-quantitative yield and 100% Faradaic efficiency at ambient conditions without the use of precious-metal catalysts for this reaction, which is also thermodynamically and kinetically more favorable than conventional water oxidation at the anode. They thus demonstrated the utility of solar energy for biomass conversion (rather than catalysts) as well as the feasibility of using an oxidative biomass conversion reaction as an anode reaction in a hydrogen-forming PEC.
Chemistry Professor Kyoung-Shin Choi and postdoc Hyun Gil Cha said that their results suggest that solar-driven biomass conversion can be a viable anode reaction that has the potential to increase both the efficiency and the utility of PECs constructed for solar-fuel production.
Harvard hybrid “bionic leaf” converts solar energy to liquid fuel isopropanol
February 10, 2015
Scientists from a team spanning Harvard University’s Faculty of Arts and Sciences, Harvard Medical School and the Wyss Institute for Biologically Inspired Engineering at Harvard University have developed a scalable, integrated bioelectrochemical system that uses bacteria to convert solar energy into a liquid fuel. Their work integrates water-splitting catalysts comprising earth-abundant components with wild-type and engineered Ralstonia eutropha bacteria to generate biomass and isopropyl alcohol. An open access paper describing their work is published in Proceedings of the National Academy of Sciences (PNAS).
Pamela Silver, the Elliott T. and Onie H. Adams Professor of Biochemistry and Systems Biology at HMS and an author of the paper, calls the system a bionic leaf, a nod to the solar water-splitting artificial leaf invented by the paper’s senior author, Daniel Nocera, the Patterson Rockwood Professor of Energy at Harvard University. (Earlier post.)