查看更多>>摘要：Poly(heptazine imide) as a metal-free semiconductor has stimulated considerable focus in the photocatalytic nitrogen fixation. However, the weak visible light absorption and unordered migration of photogenerated carriers as well as limited active site often resulted in poor photocatalytic performance. Here, we propose a conceptual to construct directional electron delivery channel via introducing C-N and N-C-O units linked terminal melem units (PCON) using a facile copolymerizing method. The optimized PCON achieved excellent photocatalytic nitrogen fixation rate (49.11 mu mol g(-1) h(-1)) and near-IR yield in pure water without using cocatalyst, which is 11 times higher than that of pristine C3N4. Based on DFT calculation and experiment results, the superior photocatalytic performance is traced back to the integrated different linker into the framework induced n - pi * transitions and acted as charge channel and activation site, which could significantly extend light absorption to the near IR, and enhance charge separation as well as reactive activation. This study lay out the importance of linker engineer of the catalyst to regulate photocatalytic activity over organic-based photocatalysts.
查看更多>>摘要：Precious metal-free Fe-N-C catalysts efficiently electrocatalyze the oxygen reduction reaction both in acid and alkaline electrolyte. Their stability is however limited in acidic medium, but generally accepted to be much higher in alkaline electrolyte. Herein, by combining advanced electron and X-ray based techniques, we provide comprehensive evidence of a Fe dissolution/reprecipitation mechanism, which partially transforms single Fe atoms into Fe oxide nanoparticles and Fe carbide nanoparticles into Fe carbide core@Fe oxide shell nano particles, and is independent on the gas atmosphere used during the accelerated stress tests. Our work shows that Fe-N-C materials based on zero-valent Fe nanoparticles should be designed so that all Fe nanoparticles are protected by a defect-free graphite shell, for improved durability. For single atom Fe-N-C catalysts, the present study raises the question of a possible synergy between minute amount of Fe oxide nanoparticles and Fe-NxCy single-atom sites, leading to the higher apparent durability of this catalyst.
McMichael, S.Tolosana-Moranchel, A.Cortes, M. A. L. R. M.Hamilton, J. W. J....
13页
查看更多>>摘要：In photoelectrocatalysis (PEC) a considerable amount of research has been focused on improving the photoelectrode; however, cathodic reactions are essential to PEC disinfection. In this work, a TiO2 nanotube (TiNT) array was used as the photoanode with various cathode electrodes materials, including gas diffusion electrodes (GDE) modified with different Pt nanoparticle loadings. The highest rate of E.coli inactivation was achieved with the non-modified GDE (2.51 log) compared to Pt mesh paddle (0.79 log reduction). This was explained by the examining reactive oxygen species generated at the counter electrode, where the non-modified GDE had the highest Faradaic efficiency of 15.5% for the formation of H2O2. Modification with Pt inhibited the formation of H2O2 to below the detection limit. The TiNT photoanode was shown to generate hydroxyl radicals, but importantly, there was reduction of molecular oxygen to superoxide radical at the anode. A thin cell reactor was then constructed using the identified optimal materials and a 5.0 log reduction in E.coli was in 20 min under UVA irradiation.
查看更多>>摘要：The hollow core-shell Co9S8 @ZnIn2S4/CdS nanoreactors are fabricated by growing ZnIn2S4 nanosheets and CdS quantum dots on hollow Co9S8 nanocages for photocatalytic CO2 reduction and H-2 generation. Because of unique structural and compositional advantages, Co9S8 @ZnIn2S4/CdS exhibits a significant photocatalytic BPA degradation of 90.62%, CO production of 82.10 mu mol g(-1) h(-1), and H-2 evolution rate up to 1419.14 mu mol g(-1) h(-1). Excellent photocatalytic performances are attributed to unique core-shell architecture, which can improve the scattering and refraction efficiency of incident light, and the separation and migration of photoinduced carriers. Furthermore, Co9S8 @ZnIn2S4/CdS possesses a broad absorption spectrum facilitating outstanding photothermal performance. The photocatalytic mechanism for the nanoreactor has been discussed in detail.
NSTL
Elsevier