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Oxide perovskites have attracted great interest as materials for energy conversion due to their stability and structural tunability. La-based perovskites of 3d-transition metals have demonstrated excellent activities as electrocatalysts in water oxidation. Herein, we report the synthesis route to La-based perovskites using an environmentally friendly deep eutectic solvent (DES) consisting of choline chloride and malonic acid. The DES route affords phase-pure crystalline materials on a gram scale and results in perovskites with high electrocatalytic activity for oxygen evolution reaction. A convenient, fast, and scalable synthesis proceeds via assisted metathesis at a lower temperature as compared to traditional solid-state methods. Among LaCoO3, LaMn0.5Ni0.5O3, and LaMnO3perovskites prepared via the DES route, LaCoO3was established to be the best-performing electrocatalyst for water oxidation in alkaline medium at 0.25 mg cm–2mass loading. LaCoO3exhibits current densities of 10, 50, and 100 mA cm–2at respective overpotentials of approximately 390, 430, and 470 mV, respectively, and features a Tafel slope of 55.8 mV dec–1. The high activity of LaCoO3as compared to the other prepared perovskites is attributed to the high concentration of oxygen vacancies in the LaCoO3lattice, as observed by high-resolution transmission electron microscopy. An intrinsically high concentration of O vacancies in the LaCoO3synthesized via the DES route is ascribed to the reducing atmosphere attained upon thermal decomposition of the DES components. These findings will contribute to the preparation of highly active perovskites for various energy applications.

New porous materials, such as metal-organic frameworks (MOFs) and covalent-organic frameworks (COFs), have been actively investigated due to their environmental applications. In this study, four of such structured materials, namely Fe3O4@COF, MIL-53(Al), MIL-53(Al)-F127 and NH2-MIL-101(Fe) were synthetized. These materials have been tested for the first time for the adsorption in aqueous media of two endocrine disruptor pollutants, bisphenol A (BPA) and prednisolone (PDN). The adsorbents were characterized by the analysis of the point of zero charge (PZC), the functional groups (FTIR) and their physic-chemical structure (N2-isotherms, SEM, XRD and XPS). MIL-53-Al provided the highest uptake of both BPA (177.78 mg g−1) and PDN (280.70 mg g−1) even when using a real wastewater matrix. Additionally, this MOF resulted to be a so-called catalytic-adsorbent, maintaining an appropriate adsorbent capacity after five regenerations cycles via Fenton-like process, causing only 20% and 5% adsorption detriment for BPA and PDN, respectively. This avoids spent adsorbent disposal issues and make this new kind of adsorbent to have the potential to be used in real environmental application scenarios.

We investigate LaCo2P2as an electrocatalytic material for oxygen evolution reaction (OER) under alkaline and acidic conditions. This layered intermetallic material was prepared viaSn-flux high-temperature annealing. The electrocatalytic ink, prepared with the ball-milled LaCo2P2catalyst at the mass loading of 0.25 mg/cm2, shows OER activity at pH = 14, reaching current densities of 10, 50, and 100 mA/cm2under the overpotential of 400, 440, and 460 mV, respectively. Remarkably, the electrocatalytic performance remains constant for at least 4 days. Transmission electron microscopy reveals the formation of a catalytically active CoOxshell around the pre-catalyst LaCo2P2core during the alkaline OER. The core serves as a robust support for the in situ-formed electrocatalytic system. Similar studies under pH = 0 reveal the rapid deterioration of LaCo2P2, with the formation of LaPO4and amorphous cobalt oxide. This study shows the viability of layered intermetallics as stable OER electrocatalysts, although further developments are required to improve the electrocatalytic performance and increase the stability at lower pH values.