Durable multifunctional electrocatalysts with zero emission and high catalytic activity are desirable for environmentally benign clean energy technologies such as water-splitting devices, fuel cells, and rechargeable metal−air batteries. Herein, we investigate a new antisite disordered polycrystalline double-perovskite oxide Ca 2 FeRuO 6 (CFR) material for catalytic activity. This makes it a remarkable electrocatalyst with excellent stability in a highly alkaline (1 M KOH) medium for oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER). The bulk perovskite exhibits significant onset potentials of 0.9 V for ORR and 1.57 V vs the reversible hydrogen electrode (RHE) for OER, creating a superior bifunctional electrocatalyst. The novelty enhances for trifunctionality as it shows a moderate onset potential of −0.19 V vs RHE for HER. Substantially, the present material efficiently accelerates visible-light-driven water splitting for OER at neutral pH with excellent recyclability. The photo-/electroactive perovskite is an exceptional example of a heterogeneous catalyst for multifunctional activity. A plausible mechanistic pathway for the synergistic effects of e g orbit-filling in perovskite oxides for OER, ORR, and HER activities is proposed by density functional theory (DFT) calculations.

A series of disordered Ca1.5La0.5FeRuO6, CaLaFeRuO6 and La2FeRuO6 double perovskites was prepared by solid-state method and investigated by neutron powder diffraction, x-ray absorption near edge structure (XANES) analysis at the...

By introduction of 2-methyl-1,5-diaminopentane (DAP) and 1,4-diaminobutane (DAB) as templated ions, three new amine-templated organophosphonate open-framework compounds [H2DAP][Zn 6 (Hhedp) 2 (hedp) 2 ]•4H 2 O, I, [H2DAB]-[Zn 6 (Hhedp) 2 (hedp) 2 ]•4H 2 O, II, and [H2DAB][Zn 3 (hedp) 2 ]•2H 2 O, III, have been synthesized, structurally analyzed, and characterized for the first time. Both compounds I and II have analogous 2-D sheet structure connecting through metal and diphosphonates (1-hydroxyethane-1,1-diphosphonic acid), while the templated amines are different in the framework. Compound III consists of Zn ions and diphosphonate ligands with templated DAB, forming three-dimensional framework with interconnected 4-T, 8-T, and 12-T ring channels. To the best of our knowledge, such structural modifications with coordination variation of metal ions applying the same amine have never been reported in the organophosphonate family. The presence of mixed metal as well as different aliphatic amines plays a crucial role for the structure directing in open-framework compounds, which is noteworthy.

Finding a high nuclearity hybrid framework with novel structure and properties by an environmentally benign approach is a really challenging task. Herein, a green strategy for synthesis of a new inorganic–organic hybrid framework solid has been described. The framework contains silver sulfate clusters with nine different silver ions with shortest silver–silver connectivity. The present compound is the first example of nonanuclear silver sulfate hybrid framework with a new topology. The hybrid solid compound shows a highly active Lewis acidic nature for the various heterogeneous catalytic reactions such as cyanosilylation, ketalization, and esterification with quantitative transformation and recyclability.

We report on the coexistence of magnetic order and disorder in the atomically disordered double perovskites Ca2FeRuO6 and CaSrFeRuO6. Powder x-ray and neutron diffraction were used to investigate the crystal structure and magnetic ordering of these oxides. Both compounds are described by the orthorhombic space group Pbnm down to 3 K, where the B-site is found to be statistically occupied by Fe 3+ and Ru 5+ ions. The compound Ca2FeRuO6 shows a G-type antiferromagnetic ordering at TN ≈ 220 K, where the moments are aligned parallel to the c axis.The exchange of Ca by Sr suppresses long-range ordering in this system with the consequence that CaSrFeRuO6 shows a diffuse scattering pattern, indicating only the presence of a short-range order of the magnetic moments. Mössbauer measurements additionally reveal the coexistence of long-range ordered and paramagnetic phase in Ca2FeRuO6, and spin-glass behavior in CaSrFeRuO6. The random occupancy of iron and ruthenium atoms at the B-site gives rise to locally varying competing magnetic exchange interactions which favors the emergence of reentrant magnetism with a spin-glass-like transition at Tf ≈ 87 K for Ca2FeRuO6 and a spin-glass transition at ~65 K for CaSrFeRuO6, as evidenced by frequency dependent ac susceptibility measurements. Our results are an interesting example for crossing the borderline between antiferromagnetism and spin-glass behavior in a 3d-4d hybrid perovskite system by rather modifying structural details described by the tolerance factor of the perovskite structure than by changing the concentration of magnetic ions.