No abstract

Dedicated to Prof. Mingyuan He on the occasion of his 80th birthday. The massive release of the greenhouse gas CO 2 has resulted in numerous environmental issues. In searching for advanced technologies for CO 2 capture/conversions, recent advances in electrochemical reduction of CO 2 in molten salts shed a light on potential solutions to CO 2 mitigation. Electro-reduction of CO 2 in molten salts exhibits features like high selectivity and efficiency towards sustainable carbons and fuels, low toxicity, and possibility to combine with in situ CO 2 capture. In this Minireview, we highlight the tuning of the products in this process and mainly discuss two categories of electrolyte, carbonate-based molten salts (CMS) and those based on halides (HMS). Depending on the synthetic conditions, fuels such as CO or hydrocarbons (in the presence of hydrogen source, i. e., LiOH, NaOH, or KOH in the electrolyte) as well as high-value nanostructured carbons including carbon nanotubes, carbon nanofibers, carbon nano-onions, and graphene can be obtained with high efficiency. The synthesis parameters are compared, and the applications of as-obtained carbons are briefly summarized. Additionally, some perspectives on this technology are also discussed. 2. CO 2 Conversion in Carbonate-Based Molten Salts 2.1. Fundamentals of carbonate molten salts Molten carbonates, including alkali metal and alkali earth metal carbonates, are commonly used as electrolytes for electrolysis [a] A

Defects on carbon nanotubes (CNTs) can be used as active sites to promote the occurrence of catalytic reactions and improve the ability of catalysts. Although some progress has been made...

Inspired by the spongy bone structures, threedimensional (3D) sponge-like carbons with meso-microporous structures are synthesized through one-step electro-reduction of CO 2 in molten carbonate Li 2 CO 3 À Na 2 CO 3 À K 2 CO 3 at 580°C. SPC4-0.5 (spongy porous carbon obtained by electrolysis of CO 2 at 4 A for 0.5 h) is synthesized with the current efficiency of 96.9 %. SPC4-0.5 possesses large electrolyte ion accessible surface area, excellent wettability and electronical conductivity, ensuring the fast and effective mass and charge transfer, which make it an advcanced supercapacitor electrode material. SPC4-0.5 exhibits a specific capacitance as high as 373.7 F g À 1 at 0.5 A g À 1 , excellent cycling stability (retaining 95.9 % of the initial capacitance after 10000 cycles at 10 A g À 1 ), as well as high energy density. The applications of SPC4-0.5 in quasi-solid-state symmetric supercapacitor and all-solid-state flexible devices for energy storage and wearable piezoelectric sensor are investigated. Both devices show considerable capacitive performances. This work not only presents a controllable and facile synthetic route for the porous carbons but also provides a promising way for effective carbon reduction and green energy production.

Fullerene microcrystals have been well prepared by the conventional liquid-liquid interface precipitation (LLIP) method, and the crystal structures can be manipulated by solvent combination. Aromatic and alcoholic solvents are widely...