Synthesis of Ti4O7/Ti3O5 Dual-Phase Nanofibers with Coherent Interface for Oxygen Reduction Reaction Electrocatalysts

Systematic Study of Effective Hydrothermal Synthesis to Fabricate Nb-Incorporated TiO2 for Oxygen Reduction Reaction

Fuel cells are expected to serve as next-generation energy conversion devices owing to their high energy density, high power, and long life performance. The oxygen reduction reaction (ORR) is important for determining the performance of fuel cells; therefore, using catalysts to promote the ORR is essential for realizing the practical applications of fuel cells. Herein, we propose Nb-incorporated TiO₂ as a suitable alternative to conventional Pt-based catalysts, because Nb doping has been reported to improve the conductivity and electron transfer number of TiO₂. In addition, Nb-incorporated TiO₂ can induce the electrocatalytic activity for the ORR. In this paper, we report the synthesis method for Nb-incorporated TiO₂ through a hydrothermal process with and without additional load pressures. The electrocatalytic activity of the synthesized samples for the ORR was also demonstrated. In this process, the samples obtained under various load pressures exceeding the saturated vapor pressure featured a high content of Nb and crystalline TiNb₂O₇, resulting in an ellipsoidal morphology. X-ray diffraction results also revealed that, on increasing the Nb doping amounts, the diffraction peak of the anatase TiO₂ shifted to a lower angle and the full width at half maximum decreased. This implies that the Ti atom is exchanged with the Nb atom during this process, resulting in a decrease in TiO₂ crystallinity. At a doping level of 10%, Nb-incorporated TiO₂ exhibited the best electrocatalytic activity in terms of the oxygen reduction current (i_ORR) and onset potential for the ORR (E_ORR); this suggests that 10% Nb-doped samples have the potential for enhancing electrocatalytic activity.

Synthesis of dual-phase Ti3O5/Ti4O7 nanofibers for efficient adsorption of SARS-CoV-2

In this study, we synthesized the dual-phase Ti₃O₅/Ti₄O₇ nanofibers for efficient adsorption of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a life-threatening virus being taking millions of people lives. The Ti₃O₅/Ti₄O₇ nanofibers were synthesized by preparation of H₂Ti₃O₇ precursor, polydopamine coating and furnace calcination. Protein and phospholipid adsorption assays showed that the dual-phase nanofibers had much higher affinity to both the model molecules bovine serum album (BSA) and phosphatidylethanolamine (PE) than the control single-phase Ti₆O₁₁ nanofibers. Consistently, the dual-phase nanofibers exhibited much stronger adsorption ability to SARS-CoV-2 pseudovirus than Ti₆O₁₁. This study sheds a light on titanium oxide nanomaterials to adsorb SARS-CoV-2 for avoiding its infection and for capturing it during rapid virus detection.