Steam-Assisted Selective CO2 Hydrogenation to Ethanol over Ru-In Catalysts.

Multicomponent catalysts can be designed to synergistically combine reaction intermediates at interfacial active sites, but restructuring makes systematic control and understanding of such dynamics challenging. We here unveil how reducibility and mobility of indium oxide species in Ru-based catalysts crucially control the direct, selective conversion of CO2 to ethanol. When uncontrolled, reduced indium oxide species occupy the Ru surface, leading to deactivation. With the addition of steam as a mild oxidant and using porous polymer layers to control In mobility, Ru-In2O3 interface sites are stabilized, and ethanol can be produced with superior overall selectivity (70%, rest CO). Our work highlights how engineering of bifunctional active ensembles enables cooperativity and synergy at tailored interfaces, which unlocks unprecedented performance in heterogeneous catalysts.

Development of a versatile electrochemical cell for in situ grazing-incidence X-ray diffraction during non-aqueous electrochemical nitrogen reduction.

In situ techniques are essential to understanding the behavior of electrocatalysts under operating conditions. When employed, in situ synchrotron grazing-incidence X-ray diffraction (GI-XRD) can provide time-resolved structural information of materials formed at the electrode surface. In situ cells, however, often require epoxy resins to secure electrodes, do not enable electrolyte flow, or exhibit limited chemical compatibility, hindering the study of non-aqueous electrochemical systems. Here, a versatile electrochemical cell for air-free in situ synchrotron GI-XRD during non-aqueous Li-mediated electrochemical N2 reduction (Li-N2R) has been designed. This cell not only fulfills the stringent material requirements necessary to study this system but is also readily extendable to other electrochemical systems. Under conditions relevant to non-aqueous Li-N2R, the formation of Li metal, LiOH and Li2O as well as a peak consistent with the α-phase of Li3N was observed, thus demonstrating the functionality of this cell toward developing a mechanistic understanding of complicated electrochemical systems.

Single-Crystal LiNix Mny Co1- x - y O2 Cathodes for Extreme Fast Charging.

Ni-rich layered LiNix Mny Co1- x - y O2 (NMCs, x ≥ 0.8) are poised to be the dominating cathode materials for lithium-ion batteries for the foreseeable future. Conventional polycrystalline NMCs, however, suffer from severe cracking along the grain boundaries of primary particles and capacity loss under high charge and/or discharge rates, hindering their implementation in fast-charging electric vehicular (EV) batteries. Single-crystal (SC) NMCs are attractive alternatives as they eliminate intergranular cracking and allow for grain-level surface optimization for fast Li transport. In the present study, the authors report synthetic approaches to produce SC LiNi0.8 Co0.1 Mn0.1 O2 (NMC811) samples with different morphologies: Oct-SC811 with predominating (012)-family surface and Poly-SC811 with predominating (104)-family surface. Poly-SC811, representing the first experimentally synthesized NMC811 single crystals with (104) surface, delivers superior performance even at the ultra-high rate of 6 C. Through detailed X-ray analysis and electron microscopy characterization, it is shown that the enhanced performance originates from better chemical and structural stabilities, faster Li+ diffusion kinetics, suppressed side reactions with electrolyte, and excellent cracking resistance. These insights provide important design guidelines in the future development of fast-charging NMC-type cathode materials.