1e:T46a,Bismuth (Bi) has been known as a highly efficient electrocatalyst for CO₂ reduction reaction. Stable free-standing two-dimensional Bi monolayer (Bismuthene) structures have been predicted theoretically, but never realized experimentally. Here, we show the first simple large-scale synthesis of free-standing Bismuthene, to our knowledge, and demonstrate its high electrocatalytic efficiency for formate (HCOO^-) formation from CO₂ reduction reaction. The catalytic performance is evident by the high Faradaic efficiency (99% at -580 mV vs. Reversible Hydrogen Electrode (RHE)), small onset overpotential (<90 mV) and high durability (no performance decay after 75 h and annealing at 400 °C). Density functional theory calculations show the structure-sensitivity of the CO₂ reduction reaction over Bismuthene and thicker nanosheets, suggesting that selective formation of HCOO^- indeed can proceed easily on Bismuthene (111) facet due to the unique compressive strain. This work paves the way for the extensive experimental investigation of Bismuthene in many different fields.1f:T52c,Abstract As the last element in Group VA, bismuthene has garnered substantial interest for its unique electronic and mechanical properties and its enhanced stability. However, the mechanism that drives the light‐bismuthene interaction remains completely unclear. Herein, a sonochemical exfoliation approach is employed to deliver a successful synthesis of few‐layer bismuthene. The corresponding nonlinear optical response at the visible wavelength is investigated. The nonlinear refractive index is ∼10 −6 cm 2 /W and was measured by spatial self‐phase modulation. Thanks to its direct energy band‐gap at 1550 nm, the saturable absorption property of bismuthene is experimentally illustrated at the telecommunication band with an optical modulation depth of ∼2.03% and a saturable intensity of ∼30 MW/cm 2 . The optimization of the laser parameters resulted in the generation of an ∼652‐femtosecond optical pulse centered at 1559.18 nm. This result indicates that the bismuthene‐based saturable absorber is indeed a new and excellent material for an ultrafast saturable absorber device. Our work highlights the promise of this material in ultrafast photonics and may be considered as an important step towards bismuthene‐based photonics devices (optical modulator, optical switcher, detector, etc.).20:T438,Currently, a broad interdisciplinary research effort is pursued on biomedical applications of 2D materials (2DMs) beyond graphene, due to their unique physicochemical and electronic properties. The discovery of new 2DMs is driven by the diverse chemical compositions and tuneable characteristics offered. Researchers are increasingly attracted to exploit those as drug delivery systems, highly efficient photothermal modalities, multimodal therapeutics with non-invasive diagnostic capabilities, biosensing, and tissue engineering. A crucial limitation of some of the 2DMs is their moderate colloidal stability in aqueous media. In addition, the lack of suitable functionalisation strategies should encourage the exploration of novel chemical methodologies with that purpose. Moreover, the clinical translation of these emerging materials will require undertaking of fundamental research on biocompatibility, toxicology and biopersistence in the living body as well as in the environment. Here, a thorough account of the biomedical applications using 2DMs explored today is given.21:T4ab,Based on first-principles phonon and finite temperature molecular dynamics calculations including spin-orbit coupling, we showed that free-standing single-layer phases of bismuth, namely buckled honeycomb and asymmetric washboard structures named as bismuthene, are stable at high temperature. We studied the atomic structure, mechanical, and electronic properties of these single-layer bismuthene phases and their bilayers. The spin-orbit coupling is found to be crucial in determining lattice constants, phonon frequencies, band

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