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Significant variability issues in metal-molecule contacts, such as adsorption geometry, lead to characteristic variability in the electrical responses of individual molecules. Herein, co-assembling 1-ethylimidazole (EIM) on Au(111) has been shown to be a feasible and effective strategy for tuning the binding configurations of pyridine-linked molecular junctions in the most common aqueous environments and atmospheric environments. The single-molecule conductance measurements clearly show a transition from multiple conductance peaks to a single conductance peak with increasing EIM concentration. Raman spectroscopy and DFT calculations suggest that the thermodynamically favorable EIM adsorbate results in the vertical orientation of the bipyridine. [ABSTRACT FROM AUTHOR]

To meet increasing requirement for innovative energy storage and conversion technology, it is urgent to prepare effective, affordable, and long-term stable oxygen electrocatalysts to replace precious metal-based counterparts. Herein, a two-step pyrolysis strategy is developed for controlled synthesis of Fe 2 O 3 and Mn 3 O 4 anchored on carbon nanotubes/nanosheets (Fe 2 O 3 -Mn 3 O 4 -CNTs/NSs). The typical catalyst has a high half-wave potential (E 1/2 = 0.87 V) for oxygen reduction reaction (ORR), accompanied with a smaller overpotential (η 10 = 290 mV) for oxygen evolution reaction (OER), showing substantial improvement in the ORR and OER performances. As well, density functional theory calculations are performed to illustrate the catalytic mechanism, where the in situ generated Fe 2 O 3 directly correlates to the reduced energy barrier, rather than Mn 3 O 4 . The Fe 2 O 3 -Mn 3 O 4 -CNTs/NSs-based Zn-air battery exhibits a high-power density (153 mW cm -2 ) and satisfyingly long durability (1650 charge/discharge cycles/550 h). This work provides a new reference for preparation of highly reversible oxygen conversion catalysts., (© 2024 Wiley‐VCH GmbH.)

Transition metal catalysts are regarded as one of promising alternatives to replace traditional Pt-based catalysts for oxygen reduction reaction (ORR). In this work, an efficient ORR catalyst is synthesized by confining Fe 3 C nanoparticles into N, S co-doped porous carbon nanosheets (Fe 3 C/N,S-CNS) via high-temperature pyrolysis, in which 5-sulfosalicylic acid (SSA) demonstrates as an ideal complexing agent for iron (ΙΙΙ) acetylacetonate while g-C 3 N 4 behaves as a nitrogen source. The influence of the pyrolysis temperature on the ORR performance is strictly examined in the controlled experiments. The obtained catalyst exhibits excellent ORR performance (E 1/2  = 0.86 V; E onset  = 0.98 V) in alkaline electrolyte, coupled by exhibiting the superior catalytic activity and stability (E 1/2  = 0.83 V, E onset  = 0.95 V) to Pt/C in acidic media. In parallel, its ORR mechanism is carefully illustrated by the density functional theory (DFT) calculations, especially the role of the incorporated Fe 3 C played in the catalytic process. The catalyst-assembled Zn-air battery also exhibits a much higher power density (163 mW cm -2 ) and ultralong cyclic stability in the charge-discharge test for 750 h with a gap increase down to 20 mV. This study provides some constructive insights for preparation of advanced ORR catalysts in green energy conversion units correlated systems., (© 2023 Wiley-VCH GmbH.)