Emissions of CO
2
from fossil fuel combustion and industrial processes have been regarded as the dominant cause of global warming. Electrochemical CO
2
reduction (ECR), ideally in aqueous media, ...could potentially solve this problem by the storage of energy from renewable sources in the form of chemical energy in fuels or value-added chemicals in a sustainable manner. However, because of the sluggish reaction kinetics of the ECR, efficient, selective, and durable electrocatalysts are required to increase the rate this reaction. Despite considerable progress in using bulk metallic electrodes for catalyzing the ECR, greater efforts are still needed to tackle this grand challenge. In this Review, we highlight recent progress in using nanoengineering strategies to promote the electrocatalysts for the ECR. Through these approaches, considerable improvements in catalytic performance have been achieved. An outlook of future developments in applying and optimizing these strategies is also proposed.
Go nano, go active: the performance of catalysts for electrocatalytic CO
2
reduction can be improved by a range of nanoengineering strategies. Through these strategies, the catalyst's morphology, electronic structures and surrounding environment are finely tuned on a nanoscale.
While the current COVID-19 pandemic continues to wreak havoc on human health and national economies, conservationists are struggling to prevent misguided persecution of bats, which are misleadingly ...being blamed for spreading the disease. Although at a global level, such persecution is relatively uncommon, even a few misguided actions have the potential to cause irrevocable damage to already vulnerable species. Here, we draw on the latest findings from psychology, to explain why some conservation messaging may be reinforcing misleading negative associations. We provide guidelines to help ensure that conservation messaging is working to neutralize dangerous and unwarranted negative-associations between bats and disease-risk. We provide recommendations around three key areas of psychological science: (i) debunking misinformation; (ii) counteracting negative associations; and (iii) changing harmful social norms. We argue that only by carefully framing accurate, honest, and duly contextualized information, will we be able to best serve society and present an unbiased perspective of bats. We hope this guidance will help conservation practitioners and researchers to develop effective message framing strategies that minimize zoonotic health risks and support biodiversity and its associated ecosystem services.
•Bats risk persecution due to misguided fears associated with COVID-19.•Conservation messaging may reinforce negative links between wildlife and zoonoses.•Psychological science is key for effective conservation message framing.•Messaging should debunk misinformation while counteracting negative associations.•Framing should be accurate, honest, and highlight desirable social norms.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Boron has been explored as p-block catalysts for nitrogen reduction reaction (NRR) by density functional theory. Unlike transition metals, on which the active centers need empty d orbitals to accept ...the lone-pair electrons of the nitrogen molecule, the sp3 hybrid orbital of the boron atom can form B-to-N π-back bonding. This results in the population of the N–N π* orbital and the concomitant decrease of the N–N bond order. We demonstrate that the catalytic activity of boron is highly correlated with the degree of charge transfer between the boron atom and the substrate. Among the 21 concept-catalysts, single boron atoms supported on graphene and substituted into h-MoS2 are identified as the most promising NRR catalysts, offering excellent energy efficiency and selectivity against hydrogen evolution reaction.
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The prevalent catalysts for natural and artificial N 2 fixation are transition-metal (TM) atoms. By using density functional theory computations, several TM atoms embedded on boron sheets as N 2 ...fixation electrocatalysts were investigated in this work. Our results revealed that single ruthenium (Ru) atom-doped boron sheets exhibited outstanding catalytic activity for ammonia synthesis at ambient conditions through the distal pathway with small activation barrier of 0.42 eV; this was less than half of that of the reported flat Ru (0001) catalysts (1.08 eV). These results highlight the value of boron as a substrate for the design of single-atom catalysts due to its unique electron-deficient features.
Ultrasmall gold (Au) nanoparticles with high mass activity have great potential for practical applications in CO2 electroreduction. However, these nanoparticles often suffer from poor product ...selectivity since their abundant low‐coordinated sites are favorable for H2 evolution. In this work, a catalyst, reduced graphene oxide supported ultrasmall Au nanoparticles (≈2.4 nm) is developed which delivers high Au‐specific mass activities (>100 A g−1) and good Faradaic efficiencies (32–60%) for the CO2‐to‐CO conversion at moderate overpotentials (450–600 mV). The efficiencies can be improved to 59–75% while retaining the ultrahigh mass activities via a simple amine‐modification strategy. In addition, an amine‐structure‐dependent effect is revealed: linear amines promote the CO formation whereas the branched polyamine greatly depresses it; the increasing alkyl chain length boosts the promotion effect of linear amines. The strong Au‐amine interaction and molecular configuration induced amine coverage on the ultrasmall Au NPs may contribute to this effect.
An amine‐modified ultrasmall gold nanoparticles catalyst on reduced graphene oxide (rGO) sheets is developed for electrochemically reducing CO2 to CO with high mass activity and excellent selectivity. The modification effect is amine‐molecular‐structure dependent. Linear amine promotes this conversion whereas branched amine depresses it. This effect can be tuned at a molecular level.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Electrochemical reduction of CO2 into liquid fuels is a promising approach to achieve a carbon‐neutral energy cycle. However, conventional electrocatalysts usually suffer from low energy efficiency ...and poor selectivity and stability. A 3D hierarchical structure composed of mesoporous SnO2 nanosheets on carbon cloth is proposed to efficiently and selectively electroreduce CO2 to formate in aqueous media. The electrode is fabricated by a facile combination of hydrothermal reaction and calcination. It exhibits an unprecedented partial current density of about 45 mA cm−2 at a moderate overpotential (0.88 V) with high faradaic efficiency (87±2 %), which is even larger than most gas diffusion electrodes. Additionally, the electrode also demonstrates flexibility and long‐term stability. The superior performance is attributed to the robust and highly porous hierarchical structure, which provides a large surface area and facilitates charge and mass transfer.
Mesoporous SnO2 nanosheets grown in situ on carbon cloth are used as a robust and flexible electrode for electroreducing CO2 to formate with high efficiency and selectivity. The superior performance is due to the hierarchical structure, which provides high surface area, fast charge and mass transport, and robustness. This electrode shows promise for practical artificial photosynthesis devices.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Graphene-like carbon nitride (g-C3N4), a metal-free 2D material that is of interest as a CO2 reduction catalyst, is stabilised by corrugation in order to minimise the electronic repulsions ...experienced by the N lone pairs located in their structural holes. This conformational change not only stabilises the Fermi level in comparison with the totally planar structure, but also increases the potential depth of the π-holes, representing the active sites where the catalytic CO2 conversion takes place. Finally, as a result of corrugation, our DFT-D3 calculations indicate that the reaction Gibbs free energy for the first H(+)/e(-) addition decreases by 0.49 eV with respect to the totally planar case, suggesting that corrugation not only involves the material's stabilisation but also enhances the catalytic performance for the selective production of CO/CH3OH.
Based on the structure of the nitrogenase FeMo cofactor (FeMoco), it is reported that Fe deposited on MoS2 2D sheets exhibits high selectivity towards the spontaneous fixation of N2 against ...chemisorption of CO2 and H2O. DFT predictions also indicate the ability of this material to convert N2 into NH3 with a maximum energy input of 1.02 eV as an activation barrier for the first proton–electron pair transfer.
Bosch–Haber alternative? Mild conditions for N2 capture and catalytic conversion into NH3 is a key priority for “green fuels” technology. DFT findings show that Fe deposited on MoS2 2D sheets selectively captures N2 gas and converts N2 into NH3 with a maximum energy input of 1.02 eV, which arises from the activation barrier for the first H+/e− pair transfer.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
A carbon quantum dots (CQDs)/Cu2O heterostructure with a protruding structure is synthesized and found to offer highly efficient photocatalytic conversion of CO2 to methanol under solar‐light ...irradiation. The CQDs/Cu2O photocatalyst exhibits excellent stability during the conversion process, which is attributed to the photoinduced electron transfer properties of the CQDs.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
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