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Germanium has been recognized as a promising anode material for lithium-ion batteries (LIBs) due to its high theoretical capacity and excellent lithium-ion diffusivity. Nonetheless, it is challenging to enhance both the high-rate performance and long-term cycling stability simultaneously. This study introduces a novel heterostructure composed of germanium nanosheets integrated with graphene (Ge NSs@Gr). These nanosheets undergo an in situ phase transformation from a hydrogen-terminated multilayer germanium compound termed germanane (GeH) derived via topochemical deintercalation from CaGe 2 . This approach mitigates oxidation and prevents restacking by functionalizing the exfoliated germanane with octadecenoic organic molecules. The resultant germanium nanosheets retain their structural integrity from CaGe 2 and present an exposed, active (111) surface that features an open crystal lattice, facilitating swift lithium-ion migration conducive to lithium storage. The composite material delivers a substantial reversible capacity of 1220 mA h g -1 at a current density of 0.2 C and maintains a capacity of 456 mA h g -1 even at an ultrahigh current density of 10 C over extended cycling. Impressively, a capacity of 316 mA h g -1 remains after 5000 cycles. The exceptional high-rate performance and durable cycling stability underscore the Ge NSs@Gr anode's potential as a highly viable option for LIBs.

Photocatalytic CO 2 reduction holds promise as a future technology for the manufacture of fuels and commodity chemicals. However, factors controlling product selectivity remain poorly understood. Herein, we compared the performance of a homologous series of Zn-based layered double hydroxide (ZnM-LDH) photocatalysts for CO 2 reduction. By varying the trivalent or tetravalent metal cations in the ZnM-LDH photocatalysts (M = Ti 4+ , Fe 3+ , Co 3+ , Ga 3+ , Al 3+ ), the product selectivity of the reaction could be precisely controlled. ZnTi-LDH afforded CH 4 as the main reduction product; ZnFe-LDH and ZnCo-LDH yielded H 2 exclusively from water splitting; whilst ZnGa-LDH and ZnAl-LDH generated CO. In-situ diffuse reflectance infrared measurements, valence band XPS and density function theory calculations were applied to rationalize the CO 2 reduction selectivities of the different ZnM-LDH photocatalysts. The analyses revealed that the d-band center (ε d ) position of the M 3+ or M 4+ cations controlled the adsorption strength of CO 2 and thus the selectivity to carbon-containing products or H 2 . Cations with d-band centers relatively close to the Fermi level (Ti 4+ , Ga 3+ and Al 3+ ) adsorbed CO 2 strongly yielding CH 4 or CO, whereas metal cations with d-band centers further from the Fermi level (Fe 3+ and Co 3+ ) adsorbed CO 2 poorly, thereby yielding H 2 only (from water splitting). Our findings clarify the role of trivalent and tetravalent metal cations in LDH photocatalysts for the selective CO 2 reduction, paving new ways for the development of improved LDH photocatalyst with high selectivities to specific products., Competing Interests: Conflict of interest The authors declare that they have no conflict of interest., (Copyright © 2020. Published by Elsevier B.V.)

The development of efficient and stable electrocatalysts for the oxygen reduction reaction (ORR) is critical for the large-scale production of fuel cells. Platinum (Pt) nanoparticle catalysts show excellent performance for ORR, though the high cost of Pt is a limiting factor that directly impacts fuel cell production costs. Alloying Pt with other transition metals is an effective strategy to reduce Pt utilization whilst maintaining good ORR performance. In this work, novel hollow PtFe alloy catalysts were successfully synthesized by high-temperature pyrolysis of SiO 2 -coated Pt-Fe 3 O 4 nanoparticle dimers supported on carbon at 900 °C, followed by SiO 2 shell removal and partial dealloying of the PtFe nanoparticles formed using HF. The obtained hollow PtFe nanoparticle catalysts (denoted herein as PtFe-900) showed a 2.3-fold enhancement in ORR mass activity compared to PtFe nanoparticles synthesized without SiO 2 protection, and a remarkable 7.8-fold enhancement relative to a commercial Pt/C catalyst. Further, after 10 000 potential cycles, the ORR mass activity of PtFe-900 remained very high (90.9 % of the initial mass activity). The outstanding ORR performance of PtFe-900 can be attributed to the modification of Pt lattice and electronic structure by alloying with Fe at high temperature under the protection of the SiO 2 coating. This work guides the development of improved, highly dispersed Pt-based alloy nanoparticle catalysts for ORR and fuel cell applications., (© 2019 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The discovery of improved chemical processes for CO and CO2 hydrogenation to valuable hydrocarbon fuels and alcohols is of paramount importance for the chemical industry. Such technologies have the potential to reduce anthropogenic CO2 emissions by adding value to a waste stream, whilst also reducing our consumption of fossil fuels. Current thermal catalytic technologies available for CO and CO2 hydrogenation are demanding in terms of energy input. Various alternative technologies are now being developed for COx hydrogenation, with solar-driven processes over two-dimensional (2D) and 2D-related composite materials being particularly attractive due to the abundance of solar energy on Earth and also the high selectivity of defect-engineered 2D materials towards specific valuable products under very mild reaction conditions. This review showcases recent advances in the solar-driven COx reduction to hydrocarbons over 2D-based materials. Optimization of 2D catalyst performance demands interdisciplinary research that embraces catalyst electronic structure manipulation and morphology control, surface/interface engineering, reactor engineering and density functional theory modelling studies. Through improved understanding of the structure-performance relationships in 2D-related catalysts which is achievable through the application of modern in situ characterization techniques, practical photo/photothermal/photoelectrochemical technologies for CO and CO2 reduction to high-valuable products such as olefins could be realized in the not-too-distant future.