Endowing metal-free graphitic carbon electrodes with high electrocatalytic reactivity is a field of intense research, but remains elusive. Here, we introduce a prototypical edge-plane-site-specific engineering strategy on “herringbone” multi-walled carbon nanotubes by performing an intercalation-exfoliation and truncation process in molten inorganic salts. Controllable synthesis of the target H-MWCNTs-MS with fully exposed edge-plane sites on both the outer surface and inner channels was demonstrated. in-situ infrared spectroscopic study supports the theoretically energetic “edge-state” and identifies the reconstructed ketone/carboxyl-terminated edge sites under oxygen evolution reaction (OER) conditions. These oxygenated edge-plane sites boost charge redistribution and interlayer coupling, which essentially govern the synergistic catalysis, as evidenced by combined theoretical, electrokinetic, and H/D isotopic studies. Benefiting from the dense reactive sites and efficient electron tunneling, the H-MWCNTs-MS demonstrated impressive OER activity with an overpotential of 236 mV at a current density of 10 mA cm −2 in alkaline media, outperforming most state-of-the-art metal-free electrocatalysts reported to date. Furthermore, the catalyst displayed no noticeable degradation during 100 h of operation, indicating its potential for practical applications.
Shu Tang,Boyuan Yang,Chen Zhang,Mingtao Duan,Milike Muhai,Jingjing Dong,Jie Xing,Hao Liu,Huiying Hao
Carbon-based, hole-transport-layer-free (HTL-free) all-inorganic perovskite solar cells (C-IPSCs) encounter several challenges, including poor crystallization quality, severe surface defects that trigger nonradiative recombination, and phase instability under ambient conditions. These issues limit their efficiency and long-term stability. In this study, we propose a one-step antisolvent method that incorporates guanabenz acetate salt (GBA) as a multifunctional additive to fabricate efficient CsPbI1.8Br1.2 C-IPSCs. The C═O and C–O groups in GBA coordinate with uncoordinated Pb2+ ions through strong interactions. Simultaneously, the hydrogen bonds between GBA and dimethyl sulfoxide slow down solvent volatilization during annealing, thereby delaying phase transitions. Additionally, the hydrophobic benzene rings in GBA create a protective surface layer that shields the perovskite from moisture ingress, thus preventing the formation of the detrimental photoinactive δ-phase. This multifunctional passivation agent effectively reduces the surface defect state density of CsPbI1.8Br1.2 while simultaneously promoting grain enlargement and extending charge carrier lifetimes. Such strategic modifications significantly suppress nonradiative recombination processes, resulting in HTL-free C-IPSCs with enhanced photovoltaic performance. The optimized devices demonstrate a remarkable efficiency increase from 12.03% to 14.34%, coupled with improved long-term stability. This work highlights the synergistic role of GBA in regulating crystallization and passivating defects, thereby presenting a promising strategy for the development of high-performance HTL-free C-IPSCs.
The convenient construction of carbon-based electrochemical immunosensors with high performance is highly desirable for the efficient detection of tumor biomarkers. In this work, an electrochemical immunosensor was fabricated by integrating a biofunctionalized mesoporous silica nanochannel film with a carbon-based electrode, which can enable the sensitive determination of carcinoembryonic antigen (CEA) in serum. The commonly used carbonaceous electrode, glassy carbon electrode (GCE), was employed as the supporting electrode and was pre-treated through electrochemical polarization to achieve the stable binding of a vertically ordered mesoporous silica film with amino groups (NH2-VMSF) without the use of any adhesive layer. To fabricate the immunorecognition interface, antibodies were covalently immobilized after the amino groups on the outer surface of NH2-VMSF was derivatized to aldehyde groups. The presence of amino sites within the high-density nanochannels of NH2-VMSF can facilitate the migration of negatively charged redox probes (Fe(CN)63-/4-) to the supporting electrode through electrostatic adsorption, leading to the generation of electrochemical signals. In the presence of CEA, the formation of immunocomplexes on the recognitive interface can reduce the electrochemical signal of Fe(CN)63-/4-on the supporting electrode. Based on this principle, the sensitive electrochemical detection of CEA was achieved. CEA can be determined to range from 0.01 ng mL−1to 100 ng mL−1with a limit of detection of 6.3 pg mL−1. The fabricated immunosensor exhibited high selectivity, and the detection of CEA in fetal bovine serum was achieved.
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