Bismuth (Bi) has been known as a highly efficient electrocatalyst for CO 2 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 CO 2 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 CO 2 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.

To elaborately fabricate real‐time monitoring and therapeutic function into a biocompatible nanoplatform is a promising route in the cancer therapy field. However, the package of diagnosis and treatment into a single‐“element” nanoparticle remains challenge. Herein, ultrasmall poly(vinylpyrrolidone)‐protected bismuth nanodots (PVP‐Bi nanodots) are successfully synthesized through an ultrafacile strategy (1 min only under ambient conditions). The nanodots are easy to synthesize in both laboratory and large scale using low‐cost bismuth ingredients. PVP‐Bi nanodots with ultrasmall size show good biocompatibility. Due to the high X‐ray attenuation ability of Bi element, PVP‐Bi nanodots have prominent performance on X‐ray computed tomography (CT) imaging. Moreover, PVP‐Bi nanodots exhibit a high photothermal conversion efficiency (η = 30%) because of the strong near‐infrared absorbance, which can serve as nanotheranostic agent for photothermal imaging and cancer therapy. The subsequent PVP‐Bi‐nanodot‐mediated photothermal therapy (PTT) result shows highly efficient ablation of cancer cells both in vitro and in vivo. PVP‐Bi nanodots can be almost completely excreted from mice after 7 d. Blood biochemistry and histology analysis suggests that PVP‐Bi nanodots have negligible toxicity. All the positive results reveal that PVP‐Bi nanodots produced through the ultrafacile method are promising single‐“element” nanotheranostic platform for dual‐modal CT/photothermal‐imaging‐guided PTT.

Various polyoxometalates (POMs) were successfully immobilized to the mesoporous coordination polymer MIL-101 resulting in a series of POM-MOF composite materials POM@MIL-101 (POM = K4PW11VO40, H3PW12O40, K4SiW12O40). These materials were synthesized by a simple one-pot reaction of Keggin POMs, tetramethylammonium hydroxide (TMAH), terephthalic acid (H2bdc), and Cr(3+) ions. XRD, FTIR, thermogravimetric analyses (TG), inductively coupled plasma (ICP) spectrometry, and energy-dispersive X-ray spectroscopy (EDX) collectively confirmed the successful combination of POMs and the porous framework. Further, these composites POM@MIL-101 with different loading of POMs were achieved by variation of the POM dosage. Notably, the uptake capacity of MIL-101 towards organic pollutants in aqueous solution was significantly improved by immobilization of hydrophilic POMs into cages of MIL-101. An uptake capacity of 371 mg g(-1), comparable to that of the graphene oxide sponges, and much higher than that of the commercial activated carbon, was achieved at room temperature in 5 min when dipping 20 mg PW11V@MIL-101 in the methylene blue (MB) solution (100 mL of 100 mg L(-1) MB solution). Further study revealed that the POM@MIL-101 composite materials not only exhibited a fast adsorption rate towards dye molecules, but also possessed of selective adsorption ability of the cationic dyes in wastewater. For example, the adsorption efficiency of PW11V@MIL-101 (10 mg) towards MB (100 mL of 10 mg L(-1)) could reach 98 % in the initial 5 min, and it could capture MB dye molecules from the binary mixture of the MB and MO with similar size. Also, the POM@MIL-101 materials could be readily recycled and reused, and no POM leached in the dye adsorption process.