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The strategic design of catalysts for the oxygen evolution reaction (OER) is crucial in tackling the substantial energy demands associated with hydrogen production in electrolytic water splitting. Despite extensive research on birnessite (δ-MnO2) manganese oxides to enhance catalytic activity by modulating Mn3+species, the ongoing challenge is to simultaneously stabilize Mn3+while improving overall activity. Herein, oxygen (O) vacancies and nitrogen (N) doping have been simultaneously introduced into the MnO2through a simple nitrogen plasma approach, resulting in efficient OER performance. The optimized N-MnO2velectrocatalyst exhibits outstanding OER activity in alkaline electrolyte, reducing the overpotential by nearly 160 mV compared to pure pristine MnO2(from 476 to 312 mV) at 10 mA cm–2, and a small Tafel slope of 89 mV dec–1. Moreover, it demonstrates excellent durability over a 122 h stability test. The introduction of O vacancies and incorporation of N not only fine-tune the electronic structure of MnO2, increasing the Mn3+content to enhance overall activity, but also play a crucial role in stabilizing Mn3+, thereby leading to exceptional stability over time. Subsequently, density functional theory calculations validate the optimized electronic structure of MnO2achieved through the two engineering methods, effectively lowering the intermediate adsorption free energy barrier. Our synergistic approach, utilizing nitrogen plasma treatment, opens a pathway to concurrently enhance the activity and stability of OER electrocatalysts, applicable not only to Mn-based but also to other transition metal oxides.

Microwave-absorbing materials adapting to high temperatures and harsh environments are in great demand. Herein, a core–shelled Ti3AlC2@La2Zr2O7(TAC@LZO) composite was designed and fabricated by encapsulating the La2Zr2O7(LZO) thermal insulation ceramic on the surface of highly conductive Ti3AlC2(TAC) via chemical coprecipitation and subsequent heat treatment. The continuous LZO ceramic coating on the surface improved the oxidation resistance of the composite at 600 °C and modulated its dielectric properties. The TAC@LZO composite exhibited an excellent microwave absorption performance within the temperature range of 25–600 °C, minimum reflection loss (RLmin) < −55 dB, and effective absorption bandwidth (EAB, RL < −10 dB) of 4 GHz. This work presents an effective approach for developing stable high-temperature microwave absorbers from thermal insulation ceramics.

The nonradiative carrier recombination at the perovskite/carrier selective layer (CSL) interface was accounted for the inferior power conversion efficiency (PCE) of perovskite solar cells (PSCs), especially rigid all-inorganic perovskite (CsPbI3and CsPbBr3). In this study, targeting the poor interface, we introduce SbX3(X = Cl, Br, I) surface passivation at the CsPbBr3/carbon interface. Smoothed compressive strain, reduced defect density, and enhanced energy-level alignment were achieved simultaneously, facilitating carrier extraction at the selective interface. With the simple aqueous solution-based two-step process, the PCE of our SbI3passivated carbon-based CsPbBr3PSCs has increased from 7.81% (without passivation) to 9.69%, a ∼25% enhancement. Specifically, Voc(1.657 V) of the SbI3-passivated cells was much higher than that of the control ones (1.488 V), confirming the ameliorated interface. Finally, our unencapsulated SbI3passivated devices maintain 90% of their initial PCEs while left in the air for 30 days with a relative humidity of 60%. To conclude, we present an interfacial carrier extraction-enhanced strategy for preparing high-performance and stable CsPbBr3-based PSCs.