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Electrochemical CO2 reduction offers a promising approach to alleviate environmental and climate impacts attributed to increasing atmospheric CO2. Intensive research work has been performed over th...

Oxides composed of an oxygen framework and interstitial cations are promising cathode materials for lithium-ion batteries. However, the instability of the oxygen framework under harsh operating conditions results in fast battery capacity decay, due to the weak orbital interactions between cations and oxygen (mainly 3d–2p interaction). Here, a robust and endurable oxygen framework is created by introducing strong 4s–2p orbital hybridization into the structure using LiNi0.5Mn1.5O4 oxide as an example. The modified oxide delivers extraordinarily stable battery performance, achieving 71.4 % capacity retention after 2000 cycles at 1 C. This work shows that an orbital-level understanding can be leveraged to engineer high structural stability of the anion oxygen framework of oxides. Moreover, the similarity of the oxygen lattice between oxide electrodes makes this approach extendable to other electrodes, with orbital-focused engineering a new avenue for the fundamental modification of battery materials.

Here it was demonstrated that the decoration of gold (Au) with polyaniline is an effective approach in increasing its electrocatalytic reduction of CO2 to CO. The core-shell-structured gold-polyaniline (Au-PANI) nanocomposite delivered a CO2 -to-CO conversion efficiency of 85 % with a high current density of 11.6 mA cm-2 . The polyaniline shell facilitated CO2 adsorption, and the subsequent formation of reaction intermediates on the gold core contributed to the high efficiency observed.

The understanding of the influence of hierarchically nanostructured architectures as support materials for catalysts loading, is critical towards development of efficient electrocatalytic interfaces. The knowledge on mass transport limitation of reactants within such catalyst-support structures remains elusive. Herein, we performed systematic investigation through a novel hierarchical 1D–3D structure by loading mesoporous Pd with an average pore size of ∼10 nm and wall thickness of ∼4 nm onto highly ordered TiO2 nanotube arrays via pulse electrodeposition. Electrochemical CO2 reductions achieved a CO2-to-formate faradaic conversion efficiency of 88 ± 2% under optimal conditions. Importantly, the product selectivity is found to depend significantly on the tube length, highlighting the influence of mass transport limitations of CO2. This work offers vital insight into practical consideration in designing efficient catalyst-support interfaces with an optimal hierarchically geometry, that must optimise mass transport as well as electrochemical kinetics.

The flow‐cell design offers prospect for transition to commercial‐relevant high current density CO2 electrolysis. However, it remains to understand the fundamental interplay between the catalyst, and the electrolyte in such configuration toward CO2 reduction performance. Herein, the dramatic influence of electrolyte alkalinity in widening potential window for CO2 electroreduction in a flow‐cell system based on SnS nanosheets is reported. The optimized SnS catalyst operated in 1 m KOH achieves a maximum formate Faradaic efficiency of 88 ± 2% at −1.3 V vs reversible hydrogen electrode (RHE) with the current density of ≈120 mA cm−2. Alkaline electrolyte is found suppressing the hydrogen evolution across all potentials which is particularly dominant at the less negative potentials, as well as CO evolution at more negative potentials. This in turn widens the potential window for formate conversion (>70% across −0.5 to −1.5 V vs RHE). A comparative study to SnOx counterpart indicates sulfur also acts to suppress hydrogen evolution, although electrolyte alkalinity resulting in a greater suppression. The boosting of the electrochemical potential window, along with high current densities in SnS derived catalytic system offers a highly attractive and promising route toward industrial‐relevant electrocatalytic production of formate from CO2.

Interest in the application of semiconductors toward the photocatalytic generation of solar fuels, including hydrogen from water-splitting and hydrocarbons from the reduction of carbon dioxide, remains strong due to concerns over the continued emission of greenhouse gases as well as other environmental impacts from the use of fossil fuels. While the efficiency and durability of such systems will depend heavily on the types of the semiconductors, co-catalysts, and mediators employed, the dimensionality of the semiconductors employed can also have a significant impact. Recognizing the broad nature of this field and the many recent advances in it, this review focuses on the emerging approaches from 0-dimensional (0D) to 3-dimensional (3D) semiconductor photocatalysts towards efficient solar fuels generation. We place particular emphasis on systems that are “semi-artificial”, that is, hybrid systems that integrate naturally occurring enzymes or whole cells with semiconductor components that harvest light energy. The semiconductors in these systems must have suitable interfacial properties for immobilization of enzymes to be effective photocatalysts. These requirements are particularly sensitive to surface structures and morphology, making the semiconductor dimensionality a critical factor. In addition to providing an overview of advances towards designing 3D architecture in semi-artificial photosynthetic field, we also present recent advances in fabrication strategies for 3D inorganic photocatalysts.

Silicon-embedded porous carbon microspheres with an exceptional conductive framework for ions and electrons were obtained by electrospraying a mixed polymer solution of polystyrene and polyvinylpyrrolidone, containing silicon nanoparticles, carbon nanotubes and carbon blacks, and subsequent heat treatment. In the composite microspheres, silicon particles were embedded in the porous carbon framework composed of interwoven carbon nanotubes, filled carbon blacks and interconnected amorphous carbon derived from polymers. The cage-like porous carbon microspheres could not only accommodate the volume expansion of silicon but also ensure a robust electrical contact, fast transport for electrons and ions. Therefore, the silicon/carbon anode exhibits a high capacity of 1325 mAh g−1 at 0.2 A g−1 after 60 cycles and superior rate capability with a capacity of 925 mAh g−1 at a large current density of 5 A g−1.

We propose a facile approach to synthesise ultrathin iron oxyhydroxide nanosheets for use in catalysing the electrochemical oxygen evolution reaction. This two dimensional material lowers the overpotential and provides a platform for further performance enhancement via integration of species such as nickel into an ultrathin nanosheet structure.

Tin-based nanomaterials are attractive low cost electrocatalysts which offers prospect of large-scale CO2 reduction, particularly for selective formate production. However, drawbacks such as large overpotential, low current density and narrow electrochemical potential window render the applicability of this catalyst. Herein, we report the dramatic influence of electrolyte alkalinity in widening potential window for CO2 electroreduction in a flow-cell system based on SnS nanosheets. The optimized SnS catalyst operated in 1 M KOH enables the achievement of a maximum formate conversion Faradaic efficiency of 88 ± 2 % at -1.3 V vs. RHE with the current density of ~ 120 mA cm-2. Alkaline electrolyte was found suppressing the hydrogen evolution across all potentials which is particularly dominant at the less negative potentials, as well as CO evolution at more negative potentials which in turn widens the potential window for formate conversion (>70% at the potential range of -0.5 to -1.5 V vs. RHE). Comparison to SnOx counterpart indicates sulphur acts to suppress hydrogen evolution, although electrolyte alkalinity also plays a role in hydrogen supression. A long term current and formate conversion stability of over 30h at -1.5V vs. RHE was obtained by reducing accumulation of carbonate or bicarbonate and buffered the pH in the KOH catholyte. This study offers new insights into strategy in boosting electrochemical potential window on Sn-based catalyst operable at a wide potential window, and the integration of desirable features of a high current density and long term stable system as demonstrated in this electrocatalytic system offers promise for implementation of large-scale formate production from CO2.

The extinction peak of Pd particles generally locates at the ultraviolet light region, suggesting that only 4% of solar light can be absorbed. Furthermore, the efficiency of LSPR hot electrons converted to chemical energy of reaction is very low due to the fast relaxation of carriers. It is extremely valuable to design Pd-based catalysts which have strong response to the visible light irradiation and high efficiency in photon to chemical energy. The Pd–CeO2 catalyst was synthesized via the hexadecyltrimethylammonium bromide (CTAB) assisted liquid-phase reduction method to generate more active interfaces. The significant extinction of Pd–CeO2 in the visible to near-infrared region indicates the strong electron interaction between Pd and CeO2. LSPR hot electrons, transferring from the Pd metal particles to the conduction band of ceria, promote the dissociation of adsorbed oxygen. Therefore, the reaction temperature of CO and toluene oxidation can be significantly lowered by visible light irradiation. The ma...

Au nanoparticles and reduced graphene oxide (r-GO) co-modified TiO 2 nanotube arrays (TNTs) were prepared by a facile and green strategy based on the electro-deposition technology for detecting H 2 O 2 , O 2 and nitrite. As-prepared Au/r-GO/TNTs electrode was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). The results clearly demonstrate that the successful attachment of r-GO sheets and narrow-range distribution of Au nanoparticles on TNTs. The reduced grapheme oxide sheet can help to improve the electronic conductive performance of TNTs and prevent the agglomeration of Au nanoparticles. Electrochemical studies reveal that the Au/r-GO/TNTs electrode exhibit excellent electrocatalytic performance toward the reduction of H 2 O 2 . Under the optimal experimental condition, the sensor has a quick response to H 2 O 2 at −0.3 V with a high sensitivity (1011.35 mA M −1 cm −2 ), wide linear range (0.01–22.3 mM) and low detection limit (0.006 μM). In addition, the sensor also has good stability and excellent selectivity. Moreover, the established Au/r-GO/TNTs electrode also shows high sensitivities towards dissolved O 2 and nitrite ions, which has great potential for the development of electrochemical sensors, molecular bioelectronics devices and biosensors.

A ZP/CZ (zirconium phosphate/Ce0.5Zr0.5O2) catalyst exhibits over 80% NOx conversion from 250 to 450 °C under a high GHSV of 300000 h−1 in the presence of H2O, CO2 and C3H8. Mixing with soot leads to a decrease in NOx conversion of the catalyst at temperatures higher than 350 °C. After hydrothermal aging (760 °C for 48 h) and sulfur aging (400 °C for 48 h), ZP/CZ still possesses over 80% NOx conversions in 289–450 °C and 297–466 °C respectively, which are significantly better than those of home made Cu-SAPO-34 and vanadium catalysts at higher temperatures. These results indicate that ZP/CZ is a promising catalyst for NOx abatement for diesel engine exhausts.