The neutral oxygen reduction reaction (ORR) has attracted tremendous attention for its broad prospects in next-generation power storage systems. However, the extremely sluggish cathodic reaction process and the limited cognition of the reaction mechanism greatly hinder its practical application. Here, we demonstrate a dynamic reconstruction behavior induced by sulfur of the iron-nitrogen (Fe-N x ) species in neutral solution. Our developed FeS 1 N 3 -OH configuration effectively optimizes the reaction kinetics by regulating the adsorption energy of oxygen intermediates for central catalytic sites. Consequently, this structure exhibits over 363% enhancement in ORR mass activity compared to the pristine FeN 4 sites under neutral electrolyte. Moreover, a neutral zinc-air battery assembled with this electrocatalyst reached an ultrahigh peak power density (81.2 mW cm −2 ), robust stability (more than 100 h) as well as superior tolerance to extreme environments (operating between −20 °C and 60 °C), representing a critical breakthrough for neutral ORR exploration and application.
Water-soluble random copolypeptides bearing pyridinium tetrafluoroborate (PyBF4) and oligo-ethylene glycol (OEG) pendants (PPLG-PyBF4-r-OEG) showed SO2-induced solution phase transition. They were prepared by sequential postpolymerizations including nucleophilic substitution of poly(γ-3-chloropropyl-l-glutamate) with sodium azide to partially convert chloro groups into azido groups, copper-mediated [2 + 3] alkyne–azide 1,3-dipolar cycloaddition to conjugate OEG pendants, another nucleophilic substitution to conjugate pyridinium chloride, and ion-exchange reaction. FTIR and CD analysis revealed that PPLG-PyBF4-r-OEG samples with suitable molar content of PyBF4 (x ≤ 0.4) were water-soluble and adopted α-helical conformation in both the solid-state and aqueous solution. UV–vis spectroscopy and dynamic light scattering (DLS) results revealed that PPLG-PyBF4-r-OEG aqueous solution underwent a reversible solution phase transition by sequentially bubbling SO2 and N2. 1H NMR analysis suggested that SO2 interacted with triazole groups and induced the solution phase transition.
Bingrong Wang,Nan Zhang,Yifeng Wang,Delun Chen,Junlei Qi,Jinchun Tu
Graphical Interface construction through experimental control of the introduced anions allows the tuning of the energy bands of photoanode materials. The cooperative energy band and electronical structure of In 2 O 3 /In 2 S 3 resulted in a photocurrent of 0.6 mA⋅cm −2 when exposed to light irradiation. This strategy has practical significance for developing low-cost, high-performance PEC sensors. In the past several decades, Photoelectrochemical (PEC) sensing still remains a great challenge to design highly-efficient semiconductor photocatalysts via a facile method. It is of much importance to design and synthesize various novel nanostructured sensing materials for further improving the response performance. Herein, we present an In 2 O 3 /In 2 S 3 heterostructure obtained by combining microwave assisted hydrothermal method with S-induced phase change, whose energy band and electronic structure could be adjusted by changing the S content. Combining theoretical calculation and spectroscopic techniques, the introduction of sulfur was proved to produce multifunctional interfaces, inducing the change of phase, oxygen vacancies and band gap, which accelerates the separation of photoexcited carriers and reduces their recombination, improving the electronic injection efficiency around the interface of In 2 O 3 /In 2 S 3 . As anticipated, an enhanced glucose response performance with a photocurrent of 0.6 mA cm −2 , a linear range of 0.1–1 mM and a detection limit as low as 14.5 μM has been achieved based on the In 2 O 3 /In 2 S 3 heterostructure, which is significant superior over its pure In 2 O 3 and S-doped In 2 O 3 counterparts. This efficient interfacial strategy may open a new route to manipulate the electrical structure, and energy band structure regulation of sensing material to improve the performance of photoelectrodes for PEC.
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