A comparison of the electrochemical and physicochemical behavior of cobalt-based oxides with spinel structure MCo 2 O 4 (M = Mn, Fe, Co, Ni, and Zn) was conducted to investigate the effect of the oxidation state and cation distribution in the spinel on the electrocatalytic activity of the oxygen evolution reaction (OER) in an alkaline solution. Various spinel MCo 2 O 4 electrocatalysts were synthesized by a facile microwave-assisted synthesis and low-temperature annealing. The overpotential of these MCo 2 O 4 electrocatalysts for the OER is comparable to the reported overpotentials of catalysts based on cobalt oxides. From the findings, the catalytic activity of OER decreases in the order of ZnCo 2 O 4 > NiCo 2 O 4 > FeCo 2 O 4 > Co 3 O 4 > MnCo 2 O 4 . It was revealed that the active sites are controlled by the balance of M 3+ /M 2+ cation distribution in octahedral and tetrahedral sites and bythe bond strength between M and oxygen atoms at the catalyst surface from the direct combination of in situ X-ray absorption fine structure (XAFS) spectroscopy with the electrochemical experiments to track the oxidation state and the structural changes of electrocatalysts before and after the exposure to the OER conditions. This study provides insights into the effects of cation distributions on the OER activity and demonstrates a promising method for determining the fundamental mechanism of cationsubstituted cobalt oxides for OER.

Carbon supported Pt nanocrystals anchoring small Ru nanoclusters (Ru-co-Pt/C) could catalyze CO2 hydrogenation to form multi-carbon compounds (C2–C26) with an extraordinary C2+ selectivity of 90.1% at 130 °C.

Highly active and stable cathode catalysts are crucial functional materials for high‐performance proton exchange membrane fuel cells. Herein, robust cathode catalysts for the oxygen reduction reaction (Pt/melem‐modified carbon (MMC)) that are assembled with Pt nanoclusters (NCs) and MMC supports are reported. The mass activity (MA) of a Pt/MMC catalyst reaches 907 mA mg−1 Pt, which is 3.9 and 4.2 times over a homemade Pt/C catalyst (Pt/VXC‐72R) and a commercial Pt/C catalyst with similar Pt particle sizes, respectively. After 10 000 voltage cycles from 1.0 to 1.5 V at 60 °C, the MA of Pt/MMC decreases by only 2% from the initial value, vastly superior to that of the Pt/C catalysts. Theoretical calculations and X‐ray absorption fine structure analysis results show that chemical bonds form between Pt nanoclusters and MMC. The adsorption energies of OOH* on the catalytic sites in Pt/MMC obviously increase, while those of OH−* decrease compared with those on Pt/C, which accounts for the measured high catalytic activity, providing a promising manner to overcome the specific scaling relations between the stability of adsorbed OH−* and OOH* on a given Pt surface. The high durability of Pt/MMC derives from strong chemical interactions between Pt NCs and the support MMC.

A bis­(μ-oxo)­diiron­(IV,IV) complex as a model for intermediate Q in the methane monooxygenase reaction cycle has been prepared. The precursor complex with a [FeIIIFeIV(μ-O)2] core was fully characterized by X-ray crystallography and other spectroscopic analyses and was converted to the [FeIV 2(μ-O)2] complex via electrochemical oxidation at 1000 mV (vs Ag/Ag+) in acetone at 193 K. The UV–vis spectral features, Mössbauer parameters (ΔE Q = 2.079 mm/s and δ = −0.027 mm/s), and EXAFS analysis (Fe–O/N = 1.73/1.96 Å and Fe···Fe = 2.76 Å) support the structure of the low-spin (S = 1, for each Fe) [FeIV 2(μ-O)2] core. The rate constants of the hydrogen abstraction reaction from 9,10-dihydroanthracene at 243 K suggest the high reactivity of these synthetic bis­(μ-oxo)­diiron complexes supported by simple N4 tripodal ligand.