EES Blog

In their Energy & Environmental Science Garcia et al. report a highly efficient catalyst that enables an industrial reaction to produce hydrogen to be carried out at ambient temperature using only the power of sunlight. Hydrogen has generated a great deal of interest as a clean and efficient energy alternative to fossil fuels.

The authors showed that gold nanoparticles supported on TiO₂ could efficiently catalyse the water gas shift reaction, which converts carbon monoxide and water from steam reformation of methane into hydrogen and carbon dioxide, using light irradiation. The scientists tested a variety of TiO₂ and CeO₂ catalysts and showed that the TiO₂/Au catalyst produced more than 10,500 µmol hydrogen per gram – more than twice the amount of the next most efficient catalyst.

Read this exciting article today:

Photocatalytic Water Gas Shift using visible or simulated solar light for the efficient, room-temperature hydrogen generation
Francesc Sastre, Marica Oteri, Avelino Corma and Hermenegildo Garcia
DOI: 10.1039/C3EE40656C

Scientists in the US have developed a new lithium/polysulfide (Li/PS) semi-liquid battery for large-scale energy storage, with lithium polysulfide (Li₂S₈) in ether as a catholyte and metallic lithium as an anode.

As the catholyte is designed to cycle only in the range between sulfur and Li₂S₄ it avoids detrimental effects due to the formation and volume expansion of solid Li₂S₂/Li₂S. This proof-of-concept Li/PS battery can reach 170 W h kg^-1 and 190 W h L^-1 at its solubility limit. It achieved an energy density of 108 W h L^-1 and 97 W h kg^-1 based on the mass of the polysulphide catholyte and lithium.

The cost of raw materials in this system was as low as $45 kW h^-1 and $145 kW^-1. Moreover, no expensive ion-selective membrane is needed for this system.

Read the full details of this exciting work today:

A membrane-free lithium/polysulfide semi-liquid battery for large-scale energy storage
Yuan Yang, Guangyuan Zheng and Yi Cui
DOI: 10.1039/C3EE00072A

A new way of making semiconducting perovskite-based solar cells could result in photovoltaic devices that are 70% cheaper than current commercial models.

Although dye-sensitised solar cells (DSSCs) have been leading the charge in cheap-to-process cell designs, semiconducting perovskites have been used in recent years to replace the sensitiser in the DSSC architecture. Whilst this reduces the interfacial energy loss that plagues DSSCs, the metal oxide support layers still need to be sintered at 500°C, which is costly.

Continuing their work on a ‘meso-superstructured’ solar cell, where they simplified the design of semiconducting perovskite solar cells, EES Advisory Board member Henry Snaith and his group at the University of Oxford have used colloidal chemistry to deposit a support layer of aluminium(III) oxide. The highest temperature this method needs is a 150°C drying step, which will not only result in cheaper devices, but could also lead to better designs.

Although his device’s 12.3% efficiency is enough to rival the very best dye-sensitised solar cells, Snaith is still looking to improve efficiency, as well as stability, on his way to producing a commercial device. He is already predicting that his device will be much cheaper than existing silicon ones.

Read this HOT communication in Energy & Environmental Science today:

Low-temperature processed meso-superstructured to thin-film perovskite solar cells
James M. Ball, Michael M. Lee, Andrew Heya and Henry J. Snaith
DOI: 10.1039/C3EE40810H

Nitrogen doping of carbon-supported electrocatalysts is known to lead to a performance boost, although the reason why has not been clearly understood. This fascinating Energy and Environmental Science article contributes to a greater understanding of the effect.

Using principal component analysis (PCA) of electron energy loss spectroscopy (EELS) data, scientists from the Colorado School of Mines, Golden, CO in the USA, have made a direct observation between spatial relationship between a carbon-supported metal catalyst nanoparticle and surface-adsorbed nitrogen.

The study correlates improved catalyst-support interactions with high substrate nitrogen content in the immediate proximity of stabilised nanoparticles. The insights are applied to a prototype methanol fuel cell, which benefits in terms of performance and long-term stability.

Read the full details of this exciting work today:

Nitrogen: Unraveling the secret to stable carbon-supported Pt-alloy electrocatalysts
Svitlana Pylypenko, Albina Borisevich, Karren L More, April Corpuz, Timothy Holme, Arrelaine Dameron, Timothy Olson, Huyen Dinh, Thomas Gennett and Ryan O’Hayre
DOI: 10.1039/C3EE40189H

Scientists studying how thermoelectric power generators can be used to ‘scavenge’ electricity from waste industrial heat have discovered that the devices work more efficiently when they are pulsed with periodic waves of heat, rather than subjected to a constant heat source.

Thermoelectric generators convert heat into electricity directly, and do not feature any moving parts. They show great promise for electricity generation in factories, power plants, cars and even with solar conversion reactions.

A great deal of research effort has gone into enhancing the efficiency of the devices, but this approach represents a cost-effective route towards even better performance.

Read the full details of this exciting development:

Periodic heating amplifies the efficiency of thermoelectric energy conversion
Yan Yan and Jonathan A. Malen
DOI: 10.1039/C3EE24158K