Electrocatalytic carbon dioxide reduction to formate is desirable but challenging. Current attention is mostly focused on tin-based materials, which, unfortunately, often suffer from limited Faradaic efficiency. The potential of bismuth in carbon dioxide reduction has been suggested but remained understudied. Here, we report that ultrathin bismuth nanosheets are prepared from the in situ topotactic transformation of bismuth oxyiodide nanosheets. They process single crystallinity and enlarged surface areas. Such an advantageous nanostructure affords the material with excellent electrocatalytic performance for carbon dioxide reduction to formate. High selectivity (~100%) and large current density are measured over a broad potential, as well as excellent durability for >10 h. Its selectivity for formate is also understood by density functional theory calculations. In addition, bismuth nanosheets were coupled with an iridium-based oxygen evolution electrocatalyst to achieve efficient full-cell electrolysis. When powered by two AA-size alkaline batteries, the full cell exhibits impressive Faradaic efficiency and electricity-to-formate conversion efficiency.

The conversion of CO 2 to value-added products using electrical or solar energy represents an attractive means for the capture and utilization of atmospheric CO 2 . Formate is a popular product from CO 2 reduction, but its reaction selectivity is usually unsatisfactory. Tin-based materials have attracted most attention for formate production at present. Unfortunately, most of them only exhibit moderate selectivity in a narrow and highly cathodic potential window. In this study, we demonstrate that traditionally under-explored bismuth has a much greater potential for formate production than tin or other materials. Mesoporous bismuth nanosheets are prepared here by the cathodic transformation of atomic-thick bismuth oxycarbonate nanosheets. They enable the selective CO 2 reduction to formate with large current density, excellent Faradaic efficiency (~100%) over a broad potential window and great operation stability. Moreover, we integrate Bi nanosheets with an oxygen evolution reaction electrocatalyst in full cells, and achieve efficient and robust solar conversion of CO 2 /H 2 O to formate/O 2 .

The electroreduction of CO to CH is a highly desirable, challenging research topic. In this study, an electrocatalytic system comprising ultrathin MoTe layers and an ionic liquid electrolyte for the reduction of CO to methane is reported, efficiently affording methane with a faradaic efficiency of 83 ± 3% (similar to the best Cu-based catalysts reported thus far) and a durable activity of greater than 45 h at a relatively high current density of 25.6 mA cm (-1.0 V ). The results obtained can facilitate research on the design of other transition-metal dichalcogenide electrocatalysts for the reduction of CO to valuable fuels.

There is an enormous interest in developing safe, cost-effective and environmentally friendly technologies for nano-materials synthesis. In the present study, extracellular biosynthesis of silver nanoparticles was achieved by Epicoccum nigrum, an endophytic fungus isolated from the cambium of Phellodendron amurense. The reduction of the silver ions was monitored by UV-visible spectrophotometry, and the characterization of the Ag NPs was carried out by X-ray diffraction and transmission electron microscopy. The synthesized Ag NPs were exceptionally stable. It was found that an alkaline pH favored the formation of Ag NPs and elevated temperature accelerated the reduction process. Furthermore, the antifungal activity of the Ag NPs was assessed using a microdilution method. The biosynthesized Ag NPs showed considerable activity against the pathogenic fungi. The current research opens a new path for the green synthesis of Ag NPs and the process is easy to scale up for biomedical applications.

The biocompatibility, controllable size and crystal structure and surface functionalization ability of TNTs accelerate its efficient development in biomedical applications including implants and biosensors.