Engineering Co Vacancies for Tuning Electrical Properties of p-Type Semiconducting Co3O4 Films

Electrocatalytic reduction of furfural to furfuryl alcohol using carbon nanofibers supported zinc cobalt bimetallic oxide with surface-derived zinc vacancies in alkaline medium

Electrocatalytic hydrogenation (ECH) reduction provides an environment-friendly alternative to conventional method for the upgrade of furfural to furfuryl alcohol. At present, exploring superior catalysts with high activity and selectivity, figuring out the reduction mechanism in aqueous alkaline environment are urgent. In this work, zinc cobalt bimetallic oxide (ZnMn2O4) with surface-derived Zn2+ vacancies supported by carbon nanofibers (d-ZnMn2O4-C) was fabricated. The d-ZnMn2O4-C exhibited excellent performance in electrocatalytic reduction of furfural, high furfuryl alcohol yield (49461.1 ± 228 µmol g-1) and Faradaic efficiency (95.5 ± 0.5 %) was obtained. In-depth research suggested that carbon nanofiber may strongly promoted the production of adsorbed hydrogen (Hads), and Zn2+ vacancies may significantly lowered the energy barrier of furfural reduction to furfuryl alcohol, the synergistic effect between carbon nanofiber and d-ZnMn2O4 probably facilitated the reaction between Hads and furfuryl alcohol radical, thereby promoting the formation of furfuryl alcohol. Furthermore, the reaction mechanism was clarified by inhibitor coating and isotope experiments, the results of which revealed that the conversion of furfural to furfuryl alcohol on d-ZnMn2O4-C followed both ECH and direct electroreduction mechanism.

Pyroelectric effect mediated infrared photoresponse in Bi2Te3/Pb(Mg1/3Nb2/3)O3-PbTiO3 optothermal ferroelectric field-effect transistors

The responses of material properties to multi-field stimulation are often exploited to construct new types of multi-functional devices. Here, we demonstrate electrical, optical and thermal modulation of the electronic properties of optothermal ferroelectric field-effect transistors (FeFETs) which are fabricated by growing Bi₂Te₃ films on (111)-oriented 0.71Pb(Mg_1/3Nb_2/3)O₃-0.29PbTiO ₃ (PMN-PT) ferroelectric single-crystal substrates. Using the electric field to switch the polarization direction of PMN-PT, the carrier density and resistance of Bi₂Te₃ films are in situ, reversibly, and nonvolatilely modulated via the ferroelectric field effect. Moreover, through infrared light illumination on the bottom of PMN-PT substrates, the resistance of Bi₂Te₃ films in two polarization states could be further modulated, which is ascribed to the decreased polarization intensity at higher temperature due to the pyroelectric effect. Taking advantage of these two effects, the Bi₂Te₃/PMN-PT optothermal FeFETs exhibit multiple responses to optical and electric field stimulation at room temperature. Our work provides a strategy to design optoelectronic devices with both photodetector and memory functionalities.