Developing cost‐effective electrocatalysts for high‐selectivity CO 2 electroreduction remains challenging. We herein report a perfluorinated covalent triazine framework (CTF) electrocatalyst that displays very high ...
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Developing cost‐effective electrocatalysts for high‐selectivity CO 2 electroreduction remains challenging. We herein report a perfluorinated covalent triazine framework (CTF) electrocatalyst that displays very high selectivity in the electroreduction of CO 2 to CH 4 with a faradaic efficiency of 99.3 % in aqueous electrolyte. Systematic characterization and electrochemical studies, in combination with density functional theory calculations, demonstrate that the presence of both nitrogen and fluorine in the CTF provides a unique pathway that is inaccessible with the individual components for CO 2 electroreduction.
The connections between the building units of meta-stable lattice were generally considered to be easily disturbed during the doping process, causing serious hindrances blocking the development of functional doped mat...
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The connections between the building units of meta-stable lattice were generally considered to be easily disturbed during the doping process, causing serious hindrances blocking the development of functional doped materials. In this work, the synthesis of doped brookite, a typical meta-stable phase of TiO2, has been explored novelly by in-situ adding of cations of VIIIB and IB,IIB elements in the 3rd period（Fe, Co, Ni, Cu, Zn） during the urea-lactate aided low-basicity hydrothermal process. The results showed that only Cu-doped brookite could be successfully synthesized with trace amount of copper intensively internalized into the brookite lattice, while the other dopants lead to the formation of anatase TiO2. Extensive characterizations indicated a two-step doping process, where copper ions were firstly dispersed in an amorphous layer on the lattice surface and then they were internalized into brookite lattice. Cu-doped brookite exhibited significantly enhanced photocatalytic activity in the phenol degradation under visible light compared to bare brookite. The enhancement of catalytic performance was assigned to the impurity band gap and the reduction of charge carriers＇ recombination introduced by the internalization of Cu ions. The investigation reported herein contributes to the understanding of complex ion-doping effects on the structures of meta-stable materials, and provides hints for obtaining other functional doped materials.
An alkaline–acid Zn–H 2 O fuel cell is proposed for the simultaneous generation of electricity with an open circuit voltage of about 1.25 V and production of H 2 with almost 100 % Faradic efficiency. We demonstrate ...
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An alkaline–acid Zn–H 2 O fuel cell is proposed for the simultaneous generation of electricity with an open circuit voltage of about 1.25 V and production of H 2 with almost 100 % Faradic efficiency. We demonstrate that, as a result of harvesting energy from both electrochemical neutralization and electrochemical Zn oxidation, the as‐developed hybrid cell can deliver a power density of up to 80 mW cm −2 and an energy density of 934 Wh kg −1 and maintain long‐term stability for H 2 production with an output voltage of 1.16 V at a current density of 10 mA cm −2 .
As a promising technique for CO 2 fixation/utilization and energy conversion/storage, the metal–CO 2 battery has been studied to improve its interconversion between CO 2 and carbonates/oxalates. Herein, we propose an...
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As a promising technique for CO 2 fixation/utilization and energy conversion/storage, the metal–CO 2 battery has been studied to improve its interconversion between CO 2 and carbonates/oxalates. Herein, we propose and realize a reversible aqueous Zn–CO 2 battery based on the reversible conversion between CO 2 and liquid HCOOH on a bifunctional Pd cathode. The 3D porous Pd interconnected nanosheet with enriched edge and pore structure, has a highly electrochemical active surface to facilitate simultaneous selective CO 2 reduction and HCOOH oxidation at low overpotentials. The resulting battery has a 1 V charge voltage, a cycling durability over 100 cycles, and a high energy efficiency of 81.2 %. The battery mechanism is proposed as Zn+CO 2 +2 H + +2 OH − ↔ ZnO+HCOOH+H 2 O, through which the reversible conversion between CO 2 and liquid HCOOH was realized.
A covalent organic framework integrating naphthalenediimide and triphenylamine units (NT‐COF) is presented. Two‐dimensional porous nanosheets are packed with a high specific surface area of 1276 m 2 g −1 . Photo/ele...
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A covalent organic framework integrating naphthalenediimide and triphenylamine units (NT‐COF) is presented. Two‐dimensional porous nanosheets are packed with a high specific surface area of 1276 m 2 g −1 . Photo/electrochemical measurements reveal the ultrahigh efficient intramolecular charge transfer from the TPA to the NDI and the highly reversible electrochemical reaction in NT‐COF. There is a synergetic effect in NT‐COF between the reversible electrochemical reaction and intramolecular charge transfer with enhanced solar energy efficiency and an accelerated electrochemical reaction. This synergetic mechanism provides the key basis for direct solar‐to‐electrochemical energy conversion/storage. With the NT‐COF as the cathode materials, a solar Li‐ion battery is realized with decreased charge voltage (by 0.5 V), increased discharge voltage (by 0.5 V), and extra 38.7 % battery efficiency.
K 2 TiF 6 :Mn 4+ is a highly efficient narrow‐band emission red phosphor with promising applications in white light‐emitting diodes (LEDs) and wide‐gamut displays. Nevertheless, the poor moisture‐resistant propert...
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K 2 TiF 6 :Mn 4+ is a highly efficient narrow‐band emission red phosphor with promising applications in white light‐emitting diodes (LEDs) and wide‐gamut displays. Nevertheless, the poor moisture‐resistant properties of this material hinder commercialization. A convenient reverse cation‐exchange strategy is introduced for constructing a core–shell‐structured K 2 TiF 6 :Mn 4+ @K 2 TiF 6 phosphor. The outer K 2 TiF 6 shell acts as a shield for preventing moisture in the air from hydrolyzing the internal MnF 6 2− group, while effectively cutting off the path of energy migration to surface defects, thereby increasing the emission efficiency (especially for the phosphors doped with high concentrations of Mn 4+ ). Employed as a red phosphor, the packaged white LED exhibits an extraordinarily high luminous efficacy of 162 lm W −1 , a correlated color temperature (CCT) of 3510 K, and a color rendering index of 93 (R a ). Aging tests performed on this device at 85 °C and 85 % humidity for 480 h retain up to 89 % luminous efficacy. The findings could facilitate commercial application of K 2 TiF 6 :Mn 4+ @K 2 TiF 6 phosphor.
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