The rational design of highly efficient, low-cost, and durable electrocatalysts to replace platinum-based electrodes for oxygen reduction reaction (ORR) is highly desirable. Although atomically dispersed supported metal catalysts often exhibit excellent catalytic performance with maximized atom efficiency, the fabrication of single-atom catalysts remains a great challenge because of their easy aggregation. Herein, a simple ionothermal method was developed to fabricate atomically dispersed Fe−N x species on porous porphyrinic triazine-based frameworks (FeSAs/PTF) with high Fe loading up to 8.3 wt %, resulting in highly reactive and stable single-atom ORR catalysts for the first time. Owing to the high density of single-atom Fe−N 4 active sites, highly hierarchical porosity, and good conductivity, the as-prepared catalyst FeSAs/PTF-600 exhibited highly efficient activity, methanol tolerance, and superstability for oxygen reduction reaction (ORR) under both alkaline and acidic conditions. This work will bring new inspiration to the design of highly efficient noble-metal-free catalysts at the atomic scale for energy conversion.

The electrocatalytic conversion of CO 2 into valueadded chemicals is apromising approach to realize ac arbonenergy balance.H owever,l ow current density still limits the application of the CO 2 electroreduction reaction (CO 2 RR). Metal-organic frameworks (MOFs) are one class of promising alternatives for the CO 2 RR due to their periodically arranged isolated metal active sites.H owever,t he poor conductivity of traditional MOFs usually results in al ow current density in CO 2 RR. We have prepared conductive two-dimensional (2D) phthalocyanine-based MOF (NiPc-NiO 4 )n anosheets linked by nickel-catecholate,w hichc an be employed as highly efficient electrocatalysts for the CO 2 RR to CO.T he obtained NiPc-NiO 4 has ag ood conductivity and exhibited av ery high selectivity of 98.4 %t oward CO production and al arge CO partial current density of 34.5 mA cm À2 ,o utperforming the reported MOF catalysts.T his work highlights the potential of conductive crystalline frameworks in electrocatalysis.

Covalent organic frameworks (COFs) are promising candidates for electrocatalytic reduction of carbon dioxide into valuable chemicals due to their porous crystalline structures and tunable single active sites, but the low conductivity leads to unmet current densities for commercial application. The challenge is to create conductive COFs for highly efficient electrocatalysis of carbon dioxide reduction reaction (CO2RR). Herein, a porphyrin‐based COF containing donor–acceptor (D–A) heterojunctions, termed TT‐Por(Co)‐COF, is constructed from thieno[3,2‐b]thiophene‐2,5‐dicarbaldehyde (TT) and 5,10,15,20‐tetrakis(4‐aminophenyl)‐porphinatocobalt (Co‐TAPP) via imine condensation reaction. Compared with COF‐366‐Co without TT, TT‐Por(Co)‐COF displays enhanced CO2RR performance to produce CO due to its favorable charge transfer capability from the electron donor TT moieties to the acceptor Co‐porphyrin ring active center. The combination of strong charge transfer properties and enormous amount of accessible active sites in the 2D TT‐Por(Co)‐COF nanosheets results in good catalytic performance with a high Faradaic efficiency of CO (91.4%, −0.6 V vs reversible hydrogen electrode (RHE) and larger partial current density of 7.28 mA cm−2 at −0.7 V versus RHE in aqueous solution. The results demonstrate that integration of D–A heterojunctions in COF can facilitate the intramolecular electron transfer, and generate high current densities for CO2RR.

Electroreduction of CO 2 (CO 2 RR) into value-added fuels is of significant importance but remains a big challenge because of poor selectivity, low current density, and large overpotential. Crystalline porous covalent organic frameworks (COFs) are promising alternative electrode materials for CO 2 RR owing to their tunable and accessible single active sites. However, the poor electron-transfer capability of COFs limits their application. Herein, a tetrathiafulvalene (TTF) strut was integrated into a two-dimensional cobalt porphyrin-based COF (TTF-Por(Co)-COF) to enhance its electron-transfer capability from the TTF to the porphyrin ring. Compared with COF-366-Co without TTF, TTF-Por(Co)-COF showed enhanced CO 2 RR performance in water with 95% Faradaic efficiency of the CO 2 -to-CO conversion at −0.7 V vs RHE and a partial current density of 6.88 mA cm −2 at −0.9 V vs RHE. This work provides a new insight for the rational design of porous organic framework materials for improving the activity of CO 2 RR.

The design and synthesis of metal-organic frameworks (MOFs) enclosed with multiple catalytic active sites is favorable for cooperative catalysis, but is is still challenging. Herein, we developed a sequential postsynthetic ionization and metalation strategy to prepare bifunctional multivariate Zr-MOFs incorporating zinc porphyrin and imidazolium functionalities. Using this facile strategy, tetratopic [5,10,15,20-tetrakis(4-carboxyphenyl)porphyrinato]zinc(II) (ZnTCPP) ligands were successfully installed into the cationic Zr-MOF to obtain ZnTCPP⊂(Br)Etim-UiO-66. These MTV-MOFs, including TCPP⊂Im-UiO-66, TCPP⊂(Br)Etim-UiO-66, and ZnTCPP⊂(Br)Etim-UiO-66, were well characterized and used in CO capture and conversion into cyclic carbonate from allyl glycidyl ether and CO under cocatalyst-free and 1 bar CO pressure conditions. It was found that the structural features and CO affinity properties of these MTV-MOFs can be tuned by introducing imidazolium groups or doping zinc sites. Additionally, ZnTCPP⊂(Br)Etim-UiO-66 exhibited enhanced catalytic activities compared to other MTV-MOFs herein for obtaining the 3-allyloxy-1,2-proplyene carbonate product, which was attributed to the cooperative effect of Zn sites and Br ions in this microporous ionic MTV-MOF. ZnTCPP⊂(Br)Etim-UiO-66 can be recycled easily and used at least three times.

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Three different experimental routes to in situ characterization of electronic structure and chemical composition of thin film cathode surfaces used in lithium ion batteries are presented. The focus is laid on changes in electronic structure and chemical composition during lithium intercalation and deintercalation studied by photoelectron spectroscopy and related techniques. At first, results are shown obtained from spontaneous intercalation into amorphous or polycrystalline V 2 O 5 thin films after lithium deposition. Although this technique is simple and clean, it is nonreversible and only applicable to the first lithium intercalation cycle into the cathode only to be applied to host materials stable in the delithiated stage. For other cathode materials, as LiCoO 2 , a real electrochemical setup has to be used. In our second approach, the experiments are performed in a specially designed electrochemical cell directly connected to the vacuum system. First experimental results of RF magnetron sputtered V 2 O 5 and LiCoO 2 thin film cathodes are presented. In the third approach, an all solid-state microbattery cell must be prepared inside the vacuum chamber, which allows electrochemical processing and characterization by photoelectron spectroscopy in real time. We will present our status and experimental difficulties in preparing such cells.