Synergistic barium titanate/MXene composite as a high-performance piezo-photocatalyst for efficient dye degradation.

Piezo-photocatalysis combines photocatalysis and piezoelectric effects to enhance catalytic efficiency by creating an internal electric field in the photocatalyst, improving carrier separation and overall performance. This study presents a high-performance piezo-photocatalyst for efficient dye degradation using a synergistic barium titanate (BTO)-MXene composite. The composite was synthesized via a facile method, combining the unique properties of BTO nanoparticles with the high conductivity of MXene. The structural and morphological analysis confirmed the successful formation of the composite, with well-dispersed BTO nanoparticles on the MXene surface. The piezo-photocatalytic activity of the composite was evaluated using a typical dye solution (Rhodamine B: RhB) under ultraviolet irradiation and mechanical agitation. The results revealed a remarkable enhancement in dye degradation (90 % in 15 min for piezo-photocatalysis) compared to individual stimuli (58.2 % for photocatalysis and 95.8 % in 90 min for piezocatalysis), highlighting the synergistic effects between BTO and MXene. The enhanced catalytic performance was attributed to the efficient charge separation and transfer facilitated by the composite's structure, leading to increased reactive species generation and dye molecule degradation. Furthermore, the composite exhibited excellent stability and reusability, showcasing its potential for practical applications in wastewater treatment. Overall, this work represents a promising strategy for designing high-performance synergistic catalysts, addressing the pressing need for sustainable solutions in environmental remediation.

Stabilizing High-Voltage Performance of Nickel-Rich Cathodes via Facile Solvothermally Synthesized Niobium-Doped Strontium Titanate.

Ni-rich layered ternary cathodes are promising candidates thanks to their low toxic Co-content and high energy density (∼800 Wh/kg). However, a critical challenge in developing Ni-rich cathodes is to improve cyclic stability, especially under high voltage (>4.3 V), which directly affects the performance and lifespan of the battery. In this study, niobium-doped strontium titanate (Nb-STO) is successfully synthesized via a facile solvothermal method and used as a surface modification layer onto the LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode. The results exhibited that the Nb-STO modification significantly improved the cycling stability of the cathode material even under high-voltage (4.5 V) operational conditions. In particular, the best sample in our work could provide a high discharge capacity of ∼190 mAh/g after 100 cycles under 1 C with capacity retention over 84% in the voltage range of 3.0-4.5 V, superior to the pristine NCM811 (∼61%) and pure STO modified STO-811-600 (∼76%) samples under the same conditions. The improved electrochemical performance and stability of NCM811 under high voltage should be attributed to not only preventing the dissolution of the transition metals, further reducing the electrolyte's degradation by the end of charge, but also alleviating the internal resistance growth from uncontrollable cathode-electrolyte interface (CEI) evolution. These findings suggest that the as-synthesized STO with an optimized Nb-doping ratio could be a promising candidate for stabilizing Ni-rich cathode materials to facilitate the widespread commercialization of Ni-rich cathodes in modern LIBs.

Engineering work functions of cobalt-doped manganese oxide based electrocatalysts for highly efficient oxygen evolution reaction.

The crystalline and electronic structures are two important factors for the design of electrocatalysts. In this work, Co-doped MnO electrocatalysts grown on nickel foam (NF) were prepared by a facile hydrothermal reaction, followed by H2 treatment process. The electrocatalytic performance of MnO was significantly improved after doping with Co and the Co0.1Mn0.9O-NF sample achieved excellent oxygen evolution reaction (OER) performance with low overpotential (370 mV at 10 mA cm-2) and reasonable Tafel slope (85.6 mV dec-1). Significantly, the low work function was obtained in the Co0.1Mn0.9O-NF sample (4.37 eV), which could accelerate the charge transfer process of the OER activity. The excellent OER performance of the Co0.1Mn0.9O-NF sample is also attributed to the rich active sites, which improved electrical conductivity and enlarged electrochemical surface areas.