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Fixing the greenhouse gas CO2 through epoxide helps to mitigate worldwide ecological troubles. The applications of metal‐free and solvent‐free catalysts remain a challenge for CO2 catalytic conversion. In this work, an array of quaternary ammonium salts derived from polyethyleneimine with hydroxyl groups ([PEI‐GDMAB‐Cn]Br) were constructed by the reaction of branched PEI with a molecular weight of 10000 and glycidyl alkyl dimethylammonium bromide. A range of experiments were designed to demonstrate that [PEI‐GDMAB‐Cn]Br can be considered as a valid metal‐free and solvent‐free homogeneous catalyst for the CO2‐epoxide cycloaddition reaction. Among of [PEI‐GDMAB‐Cn]Br, [PEI‐GDMAB‐C18]Br catalyzed the model reaction of CO2 and epichlorohydrin under optimized reaction conditions (T=80 °C, 1.0 atm CO2, catalyst 1 mol%, ECH 15 mmol, 16 h) and the conversion achieved at 97.5 %. Moreover, the catalyst exhibited stable reusability and broad substrate applicability, which was used in the following cycle succinctly, because of self‐separated properties by temperature control. The [PEI‐GDMAB‐C18]Br catalyzed reaction process was detected as a pseudo‐first‐order reaction after kinetic studies and an Ea was calculated to be 50.65 kJ/mol. A combinatorial catalytic mechanism of hydrogen bonding and bromide ions is suggested to explain the remarkable catalytic performance of this bifunctional catalyst. [ABSTRACT FROM AUTHOR]

By pyrolyzed the products from hydrothermal reaction of 1, 4, 5, 8‐naphthalene tetramethyl anhydride, NaOH and FeSO4, the nanoparticles of FeFe2O4 were produced, and then its electrochemical performance of oxygen reduction reaction (ORR) was evaluated in O2 saturated 0.1 M KOH solution. The results indicated that, among all the as‐prepared samples, FeFe2O4‐0.50 was mainly composed of uniformly dispersed spherical nanoparticles of 20‐30nm and behaved the best ORR catalytic performance. Its half‐wave potential and limiting diffusion current density was 0.61 V and −1.85 mA cm−2@0.4 V vs. RHE), respectively, higher about 20 mV and 1.29 mA cm−2 than that of FeFe2O4 (0.59 V and −0.56 mA cm−2@0.4 V vs. RHE). In addition, FeFe2O4‐0.50 also showed stronger stability as well as methanol/CO tolerance than that of commercial 20 % Pt/C. It was the evenly dispersed FeFe2O4 nanoscale and Fe−O bond in FeFe2O4‐0.50 that contributed its excellent electrochemical performance and tolerance for CO and methanol. The as‐prepare FeFe2O4‐0.50 might be a potential alternative catalyst for ORR in fuel cell. [ABSTRACT FROM AUTHOR]