Disentangling Local Interfacial Confinement and Remote Spillover Effects in Oxide–Oxide Interactions

Abstract

Supported oxides are widely used in many important catalytic reactions, in which the interaction between the oxide catalyst and oxide support is critical but still remains elusive. Here, we construct a chemically bonded oxide−oxide interface by chemical deposition of Co 3 O 4 onto ZnO powder (Co 3 O 4 /ZnO), in which complete reduction of Co 3 O 4 to Co 0 has been strongly impeded. It was revealed that the local interfacial confinement effect between Co oxide and the ZnO support helps to maintain a metastable CoO x state in CO 2 hydrogenation reaction, producing 93% CO. In contrast, a physically contacted oxide−oxide interface was formed by mechanically mixing Co 3 O 4 and ZnO powders (Co 3 O 4 −ZnO), in which reduction of Co 3 O 4 to Co 0 was significantly promoted, demonstrating a quick increase of CO 2 conversion to 45% and a high selectivity toward CH 4 (92%) in the CO 2 hydrogenation reaction. This interface effect is ascribed to unusual remote spillover of dissociated hydrogen species from ZnO nanoparticles to the neighboring Co oxide nanoparticles. This work clearly illustrates the equally important but opposite local and remote effects at the oxide−oxide interfaces. The distinct oxide− oxide interactions contribute to many diverse interface phenomena in oxide−oxide catalytic systems.

RuO2–CeO2 Lattice Matching Strategy Enables Robust Water Oxidation Electrocatalysis in Acidic Media via Two Distinct Oxygen Evolution Mechanisms

“…Decarbonizing the global energy sector requires the rapid growth of a green hydrogen economy. − Electrocatalytic water splitting is widely considered the best approach for producing hydrogen at scale to support a green hydrogen energy infrastructure, with hydrogen ideally being produced from electricity generated by solar photovoltaics, wind turbines, or hydroelectric turbines. − The two mainstream water splitting technologies currently employed for hydrogen production are proton exchange membrane water electrolyzers (PEMWEs) and alkaline water electrolyzers. Compared to alkaline water electrolysis, PEMWEs offer many advantages including higher energy efficiency, higher current densities, and a purer hydrogen product. , …”

“…However, a strongly acidic working environment necessitates the use of noble metal catalysts in commercial PEMWEs. For instance, platinum is typically employed for the hydrogen evolution reaction (HER) at the cathode, while iridium is used for the oxygen evolution reaction (OER) at the anode. − Unfortunately, this reliance on noble metal catalysts impedes the widespread adoption of this technology. ,, The energy barrier associated with the OER, which involves four-electron transfer steps, is much higher than that of the HER, which involves only two electron transfer steps. Consequently, PEMWEs typically use 5 times more iridium at the anode relative to platinum at the cathode to achieve an optimal performance.…”

Spatially and Temporally Resolved Dynamic Response of Co-Based Composite Interface during the Oxygen Evolution Reaction

“…Correspondingly, the interfacial interaction may also exhibit certain “size” characteristics once the composite structure forms the interface. Bao et al proposed that only CoO x close to the Co 3 O 4 /ZnO interface can be stabilized, while that farther from the interface cannot be maintained and instead becomes Co 0 , resulting in a change in product selectivity in the CO 2 hydrogenation reaction . Although these studies have consciously raised inconsistencies in the catalytic properties of heterogeneous structures at spatial scales, key fundamental issues concerning the interfacial microenvironment have not been elucidated so far.…”

Stabilized inverse Y2O3/Cu interfaces boost the performance of the reverse water–gas shift reaction

“…The construction of stable metal–oxide interfaces has been a hot topic in the field of heterogeneous catalysis, especially conventional supported catalysts. 12–15 Stable Cu-oxide interfaces can be maintained by decreasing Cu loading to fabricate highly dispersed Cu sites, designing reducible oxide shells to obtain the SMSI effect and synthesizing Cu-based catalysts with special spinel structures. 6,16–22 However, these methods inevitably lead to fewer initial or exposed active Cu species, resulting in unsatisfactory catalytic activity.…”