Phosphors are efficient luminescent materials that are being extensively used in lighting and displays in today's world.

Metal organic frameworks (MOFs), an emerging class of nanoporous crystalline materials, have become increasingly attractive for solar energy applications. In this work, we report a newly designed mixed-node MOF catalyst, Co x Fe1–x -MOF-74 (0 < x ≤ 1), which acts as a highly efficient electrocatalyst for oxygen evolution reaction (OER) in alkaline solution with remarkably low overpotential (280 mV at a current density of 10 mA/cm2), small Tafel slope (56 mV/dec), and high faradic efficiency (91%) and can deliver a current density of 20 mA/cm2 at 1.58 V for overall water splitting. Moreover, using the combination of multiple spectroscopic methods, including X-ray absorption, electron spin resonance, and X-ray photoelectron spectroscopy, etc., we unraveled the mechanistic origin of the enhanced catalytic performance of Co x Fe1–x -MOF-74 compared to its single-metal counterparts. We show the mixed-node MOF can provide more open metal sites and an enhanced electron-rich environment, which facilitates efficient charge transfer and results in significantly enhanced OER activity.

Electrochemical activation is an effective and simple method to obtain in-situ surface modification of MOF materials away from thermal decomposition. However, the impact of the rate and related phase transformation on OER intrinsic activity during the electrochemical activation process is often overlooked. Herein, we synthesized a kind of Co-MOF with a unique crystal structure in which the center metals were coordinated with the oxygen and nitrogen atoms from two water molecules and organic linkers. The bond strength between the center metals and the coordinated water molecules can be modulated by introducing Fe into Co-MOF, causing the expedited electrochemical activation. First-principles calculations suggest the electronic state of cobalt in CoFe-MOF can be modified to alter the free energy of adsorbed intermediates. Therefore, the obtained electrocatalyst possesses the optimal OER intrinsic activity, showing a low overpotential of 265 mV at 10 mA cm–2, a small Tafel slope of 44 mV dec–1, and a long-term electrochemical durability with a period of 40 h. The findings are expected to help understand the fundamental principles of electrochemical activation.

Well-ordered NiFe-MOF-74 is in situ grown on Ni foam by the induction of Fe2+ and directly used as an OER electrocatalyst. Benefited from the intrinsic open porous structure of MOF-74, the in situ formed MOF arrays and the synergistic effect of Ni and Fe, outstanding water oxidation activity is obtained in alkaline electrolytes with an overpotential of 223 mV at 10 mA cm-2.

Developing highly efficient oxygen evolution reaction (OER) electrocatalysts is critical to the cost-effective generation of clean fuels. Transition-metal selenides have been proposed to be OER catalyst alternatives to noble metal based catalysts, but generally exhibit limited electrocatalytic activity. We here report hierarchical Fe-doped NiSe ((Ni,Fe)Se) ultrathin nanosheets as an efficient electrocatalyst for OER in alkaline electrolytes. The preparation involves a solvothermal synthesis and a topotactic conversion process. The prepared hierarchical (Ni,Fe)Se ultrathin nanosheets show abundant and accessible catalytically active sites, facile charge transfer and a high specific surface area. Relative to the NiSe nanosheets, the as-prepared (Ni,Fe)Se ultrathin nanosheets show a higher current density and a lower Tafel slope towards the OER. Remarkably, hierarchical (Ni,Fe)Se ultrathin nanosheets supported on Ni foam exhibit an electrocatalytic OER with a current density of 10 mA cm at a low overpotential of 225 mV and a small Tafel slope of about 41 mV dec. This study establishes (Ni,Fe)Se ultrathin nanosheets as an efficient electrocatalyst for the OER that can be used in the fields of metal-air batteries and water splitting for hydrogen production.

We report on the design of ultraviolet (UV) emitting persistent (PersL) materials.

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The oxygen evolution reaction (OER) accompanied by multistep proton-coupled electron transfer is the decisive step of electrochemical water splitting due to the sluggish kinetics process. Enhancing the efficiency of water splitting indispensably requires stable and high-efficiency electrocatalysts for OER. The OER activity of electrocatalysts can be largely heightened by well adjusting their energy level and active sites. Herein, the amorphous iron cobalt molybdenum carbonate hydroxide core–shell microspheres (FeCoMo/CoMo) offer significant opportunities to improve the OER activity in both thermodynamics and kinetics due to the appropriate matching of the energy level with the equilibrium potential of OER and the abundant active sites.The well-designed Fe0.25–CoMoCH/NF sample exhibits prominent activity toward OER with an overpotential as low as 232 mV to deliver a current density of 10 mA cm–2, a small Tafel slope of 46 mV dec–1, and excellent stability in alkaline solution. Mechanistic studies using a rotating ring-disk electrode confirm the four-electron pathway with high faradaic efficiency (97.7%) toward OER. This research provides a model system so as to tune the inherent catalytic activity of electrocatalysts.