Two-dimensional (2D) graphitic-C3N4 (g-C3N4) was successfully hybridized with one-dimensional (1D) flux-grown Na-modified K2Ti6O13 nanobelts (Na-K2Ti6O13 NBs) for the first time to construct novel 1D/2D Na-K2Ti6O13/g-C3N4 heterostructured photocatalysts using a facile mixing–calcination method. The heterostructured Na-K2Ti6O13/g-C3N4 composites with three-dimensional (3D) hybrid architectures exhibited a remarkably enhanced photocatalytic efficiency for organic pollutant degradation in comparison with pure Na-K2Ti6O13 and g-C3N4 under both simulated sunlight and visible-light irradiation (λ > 420 nm), which could be mainly attributed to the synergistic effects between Na-K2Ti6O13 and g-C3N4 including more efficient interfacial charge transfer, longer lifetimes and the stronger oxidation and reduction ability of photogenerated charge carriers, fundamentally originating from the formation of Na-K2Ti6O13/g-C3N4 heterojunctions based on the well-matched energy-band structures. Moreover, the Na-K2Ti6O13/g-C3N4 hybrids showed good stability and reusability for the photocatalytic degradation of organic pollutants. Finally, the possible mechanisms responsible for the improved simulated sunlight and visible-light photocatalytic performance were also investigated, respectively, based on the results of PL spectra, time-resolved fluorescence decay spectra, radical species trapping experiments, ESR spectra and PL-TA measurements. Overall, this work will not only be beneficial for the design and development of more efficient visible-light-responsive g-C3N4-based composites for solar energy conversion and environmental remediation but will also be influential in optimizing the visible-light photocatalytic activity of wide-band-gap 1D titanate nanomaterials to meet the requirements of practical applications.
Shibo Wu,Jingrui Cao,Yang Zhou,Jiahao He,Jiangjie Zhou,Muslum Demir,Hongye Yang,Zaizai Tong,Pianpian Ma
High-entropy perovskite oxides, an emerging electrocatalytic electrode material, integrates the distinctive features of high-entropy materials and perovskites, offering significant potential in electrocatalysis. While adjusting the B-site elements has been a widely adopted approach for modulating the electrocatalytic activity of HEPs, there was a notable lack of systematic investigations into the role of A-site ions in regulating their electrocatalytic performance. To overcome this deficiency, in the present study, La 1-x Na x (CrMnFeCoNi) 1/5 O 3 HEPs were synthesized using carbon nanotubes-based sacrificial template method. It was found that the Na substitution at the A-site not only significantly reduced the synthesis temperature but also facilitated the preservation of carbon nanotubes. This retention contributed to the formation of a three-dimensional network structure, exposing a greater number of active sites. The Na modification induced significant valence fluctuations at the B-site and tailored the oxygen vacancy concentrations, enhancing the synergistic "cocktail effect" among the various metal atoms. Furthermore, the introduction of Na stimulated the formation of surface M-OOH species, which serve as active intermediates to enhance OER activity. As a result, the Na-modified HEPs demonstrated exceptional OER performance compared to their parent phases. Among these, La 0.6 Na 0.4 (CrMnFeCoNi) 1/5 O 3 (L6N4-5M) sample exhibited a lower overpotential of 313 mV at a current density of 10 mA cm −2 and a Tafel slope of 47.4 mV dec −1 . Additionally, the A-site Na modification strategy and the in-depth investigation of the OER mechanism provide valuable insights for the future design and development of high-performance HEP electrocatalysts.
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