The acetate-based ionic liquids (ILs), e.g., [ n Bu4N]­OAc, have been developed for challenging 4-electron reduction of CO2 with amines and hydrosilane to afford aminals. Notably, polymethylhydrosiloxane, a cheap byproduct of the silicone industry, also works well as a reductant. Furthermore, an alternative pathway is rationally proposed via thorough density functional theory (DFT) study. In addition, the ILs play a surprisingly significant role through decreasing activation free energy. More importantly, the essence of being kinetically favorable with 4-electron reduction and thermodynamically favorable with 6-electron reduction is unveiled by DFT study, which guides us to successfully get 6-electron reductive products of CO2, i.e., methylamine. This work represents upgrading usage of both carbon and silicon wastes to valuable chemicals via IL catalysis.

A rhenium–pyrene catalyst that dramatically promotes sunlight-induced CO2RR efficiency was developed by enhancing intermolecular electron transfer efficiency and visible light-harvesting ability.

Visible light-induced photocatalytic CO2 reduction reaction (CO2RR) is a feasible and promising option to tackle the greenhouse effect and energy crisis. Herein, two ferric porphyrin-based porous organic polymer semiconductors, hereafter referred to as POPn-Fe (porous organic polymers, n = 1 or 2, corresponding to a benzene/biphenyl unit as a linker between porphyrin units), are synthesized for the visible light-driven CO2RR to produce syngas. The CO/H2 evolution rates for POP2-Fe under irradiation >420 nm are found to successfully reach up to 3043 and 3753 μmol g–1 h–1, respectively. Interestingly, the experiment results imply that the ferric porphyrin site could be responsible for CO evolution and the uncoordinated porphyrin unit in POPn or POPn-Fe semiconductors may be obligate for H2 formation. Furthermore, as evidenced by Mott–Schottky plots, the extended π-conjugation with the biphenyl linker makes POP2-Fe a lower conduction band potential, which helps the ferric porphyrin sites capture electrons from the photosensitizer, thus producing more CO to realize selectivity control. Also, the efficient catalytic activity of POP2-Fe is presumably attributed to the accelerated charge transfer as well as facilitates photogenerated electron and hole separation. This work offers an elegant strategy to design and optimize earth-abundant metal visible light photocatalysis for CO2 reduction to syngas with CO/H2 ratio control.

The electrocatalytic CO2 reduction reaction (ECO2RR) is one promising method for storing intermittent clean energy in chemical bonds and producing fuels. Among various kinds of catalysts for ECO2RR, molecular metal complexes with well‐defined structures are convenient for studies of their rational design, structure–reactivity relationships, and mechanisms. In this Review, we summarize the molecular engineering of several N‐based metal complexes including Re/Mn bipyridine compounds and metal macrocycles, concluding with general modification strategies to devise novel molecular catalysts with high intrinsic activity. Through physical adsorption, covalent linking, and formation of a periodic backbone, these active molecules can be heterogenized into immobilized catalysts with more practical prospects. Finally, significant challenges and opportunities based on molecular catalysts are discussed.

DedicatedtoProfessor Mingyuan He on the occasion of his 80th birthday. Developing an efficient and easy-to-handle strategy in designing catalysts for CO 2 reduction into CO by harnessing sunlight is ap romising project. Here, af acile strategy was developed to design aR ec atalyst modified with an ionic secondaryc oordination sphere for photoreduction of CO 2 to CO by visible light. By adding ionic liquids or tuning ad ifferent ionic secondary coordination sphere, it was discovered that an outstanding optical property,o ther than CO 2 absorption ability or the ability to dissociation of chloride anion,i st he prerequisite for catalyst design.A ccordingly,an ovel Re catalyst, {Re[BpyMe(tris(2-hydroxyethyl)amine)](CO) 3 Cl}Br (Re-THEA), was designed, screened, and resulted in ar elative high quantum yield (up to 34 %) for visible-light-induced CO 2 reduction with as ingle-molecule system.D FT calculations, combined with experimental outcomes, suggested the pendant ionic tris(2-hydroxyethyl)amino (THEA) group on Re-THEA can enhance visible-light absorption, stabilize reaction intermediates, and suppress the Re-Re dimer formation. The increasing concentration of CO 2 in the atmosphere has caused plentyo fc limatei ssues and attracted increasing interest among governments and scientists. [1] Conversion of CO 2 into valuablep roducts, or even into fuels, is an appealing access strategy to relieve energy shortages and realize carbon cycling. [2] However,f urthere nergy input is necessary in most CO 2 conversionsb ecause of the high thermodynamic and kinetic stability of CO 2. [3] One attractive approacht oa ddress this problem is to apply sunlight, aclean, renewable, and abundant energy source, for the reduction of CO 2 to CO because CO can be easily transformed into liquid fuels throughF ischer-Tropsch synthesis. [4] Photocatalytic CO 2 reduction reaction(CO 2 RR) is a proton-coupled electron-transfer (PCET) process and typically accomplished by as ystem composed of three parts:p hotosen-[a] Dr.