Aqueous-phase oxygen evolution reaction (OER) is the bottleneck of water splitting. The formation of the O−O bond involves the generation of paramagnetic oxygen molecules from the diamagnetic hydroxides. The spin configurations might play an important role in aqueous-phase molecular electrocatalysis. However, spintronic electrocatalysis is almost an uncultivated land for the exploration of the oxygen molecular catalysis process. Herein, we present a novel magnetic Fe III site spin-splitting strategy, wherein the electronic structure and spin states of the Fe III sites are effectively induced and optimized by the Jahn−Teller effect of Cu 2+ . The theoretical calculations and operando attenuated total reflectance-infrared Fourier transform infrared (ATR FT-IR) reveal the facilitation for the O−O bond formation, which accelerates the production of O 2 from OH − and improves the OER activity. The Cu 1 −Ni 6 Fe 2 −LDH catalyst exhibits a low overpotential of 210 mV at 10 mA cm −2 and a low Tafel slope (33.7 mV dec −1 ), better than those of the initial Cu 0 −Ni 6 Fe 2 −LDHs (278 mV, 101.6 mV dec −1 ). With the Cu 2+ regulation, we have realized the transformation of NiFe−LDHs from ferrimagnets to ferromagnets and showcase that the OER performance of Cu−NiFe−LDHs significantly increases compared with that of NiFe−LDHs under the effect of a magnetic field for the first time. The magnetic-fieldassisted Cu 1 −Ni 6 Fe 2 −LDHs provide an ultralow overpotential of 180 mV at 10 mA cm −2 , which is currently one of the best OER performances. The combination of the magnetic field and spin configuration provides new principles for the development of highperformance catalysts and understandings of the catalytic mechanism from the spintronic level.

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Ultrathin two-dimensional metal−organic frameworks (2D MOFs) have the potential to improve the performance of Li−O 2 batteries with high O 2 accessibility, open catalytic active sites, and large surface areas. To obtain highly efficient cathode catalysts for aprotic Li−O 2 batteries, a facile ultrasonicated method has been developed to synthesize three kinds of 2D MOFs (2D Co-MOF, Ni-MOF, and Mn-MOF). Contributing from the inherent open active sites of the Mn−O framework, the discharge specific capacity of 9464 mAh g −1 is achieved with the 2D Mn-MOF cathode, higher than those of the 2D Co-MOF and Ni-MOF cathodes.During the cycling test, the 2D Mn-MOF cathode stably operates more than 200 cycles at 100 mA g −1 with a curtailed discharge capacity of 1000 mAh g −1 , quite longer than those of others. According to further electrochemical analysis, we observe that the 2D Mn-MOF outperforms 2D Ni-MOF and Co-MOF due to a superior oxygen reduction reactions and oxygen evolution reactions activity, in particular, the efficient oxidation of both LiOH and Li 2 O 2 . The present study provides new insights that the 2D MOF nanosheets can be well applied as the Li−O 2 cells with high energy density and long cycling life.

Urea, as a prospective energy source, is rarely utilized for lack of effective catalysts to overcome its sluggish kinetics during its electrolysis. Exploiting low-cost and high-efficiency catalysts to accelerate the urea oxidation reaction (UOR) does make sense as it can relieve not only energy shortage but also the water contamination problems. In this work, the Ni3S2 nanosheets grown on the Ni foam with different amounts of Mn2+ doping were developed as useful electrocatalysts toward UOR. The experimental and computational methods were performed to explore the properties of obtained samples. We found that the doping of Mn2+ could distinctly regulate the charge distribution of Ni3S2 by which the performance was observably optimized. We also compared the behaviors of obtained catalysts with various dopant concentrations of Mn2+. Especially, Ni3S2 grown on the Ni foam with the addition of 0.2 mmol of Mn2+ exhibits splendid properties with a lower potential and superior longevity, which can achieve a current density of 100 mA cm–2 at a voltage of only 1.397 V (vs reversible hydrogen electrode) in 1.0 M KOH containing 0.5 M urea solution, indicating that our findings can serve as promising electrocatalysts for urea electrolysis.

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MOFs present potential application in electrocatalysis. The structure–activity of the Ni-MOFs with different morphologies, nanowires, neurons, and urchins is systemically investigated. The Ni-MOFs were controllably synthesized via the facile solvothermal method. Among them, the Ni-MOF nanowires are endowed with the highest electrocatalytic activity due to the unique structure, more exposed active sites, lower charge transfer resistance, and the fast and direct electron transfer in 1D structures. The typical morphology of the Ni-MOF nanowires is ca. 10 nm in diameter and several micrometers in length. When employed as an electrocatalyst in urea oxidation reaction, it exhibits a lower overpotential than and superior stability to the Ni-MOFs with other morphologies. Ni-MOF nanowires require a potential of ∼0.80 V (vs Ag/AgCl) to obtain 160 mA cm–2. In addition, after continuous electrocatalyzing for 3600 s at 0.40 V (vs Ag/AgCl), the current density retention of Ni-MOF nanowires could still reach more than 60% (>12 mA cm–2), which demonstrates Ni-MOF nanowires as promising electrocatalysts for urea oxidation.

Two-dimensional MXene, a significant member of the two-dimensional family, has attracted much interest in physics, energy evolution, environmental science, and nanomedicine. However, the acute toxicity of fluoride-based synthetic procedures remains an impediment to large-scale fabrication and applications. It is an urgent need to develop an innocuous and effective protocol for MXene synthesis. Therefore, we developed a facile, rapid fluoride-free electrochemical etching strategy based on the selective corrosion of Al layers in titanium aluminum carbide (Ti 3 AlC 2 ) in a traditional Li-ion battery system. On the basis of the intercalation− alloying−expansion−microexplosion mechanism, single-and few-layer fluoride-free Ti 3 C 2 T x (T = O or OH) were prepared. Furthermore, the fluoride-free Ti 3 C 2 T x exhibits excellent capability for a supercapacitor. This strategy provides a safe, green, and environmentally friendly way to realize the production of ultrathin MXene materials from MAX.

Nobel metal Pt composites show high catalytic activity for hydrogen evolution reaction (HER) but limited in application by high Pt contents and therefore the cost. Herein, a series of Pt nanoparticle (NP)-deposited 2D Ti 3 C 2 T x MXenes were prepared by an atomic layer deposition (ALD) method with relatively low Pt contents (0.98−3.10 wt %) and showed excellent HER catalytic activity and stability. The electrochemical results indicated that the prepared catalysts showed the optimal HER activity as the ALD deposition cycle reached 40, with an overpotential of 67.8 mV approaching that of the commercial Pt/C catalyst (64.2 mV). The excellent behavior was attributed to the homogeneous dispersion of the Pt NPs and the good conductivity of the 2D Ti 3 C 2 T x MXene supports.