Constructing cuprous oxide-modified zinc tetraphenylporphyrin ultrathin nanosheets heterojunction for enhanced photocatalytic carbon dioxide reduction to methane.

The application of supermolecular naonostructures in the photocatalytic carbon dioxide reduction reaction (CO2RR) has attracted increasing attentions. However, it still faces significant challenges, such as low selectivity for multi-electron products and poor stability. Here, the cuprous oxide (Cu2O)-modified zinc tetraphenylporphyrin ultrathin nanosheets (ZnTPP NSs) are successfully constructed through the aqueous chemical reaction. Comprehensive characterizations confirm the formation of type-II heterojunction between Cu2O and ZnTPP in Cu2O@ZnTPP, and the electron transfer from Cu2O to ZnTPP through the Zn-O-Cu bond under the static contact. Under the visible-light irradiation (λ > 420 nm), the optimized Cu2O@ZnTPP sample as catalyst for photocatalytic CO2RR exhibits the methane (CH4) evolution rate of 120.9 µmol/g/h, which is âˆ¼ 4 and âˆ¼ 10 times those of individual ZnTPP NSs (28.0 µmol/g/h) and Cu2O (12.8 µmol/g/h), respectively. Meanwhile, the CH4 selectivity of âˆ¼ 98.7 % and excellent stability can be achieved. Further experiments reveal that Cu2O@ZnTPP has higher photocatalytic conversion efficiency than Cu2O and ZnTPP NSs, and the photoinduced electron transfer from ZnTPP to Cu2O can be identified via the path of ZnTPP→ (ZnTPP•ZnTPP)*→ ZnTPP-→ Zn-O-Cu â†’ Cu2O. Consequently, Cu2O@ZnTPP exhibits a shorter electron-hole separation lifetime (3.3 vs. 9.3 ps) and a longer recombination lifetime (23.1 vs. 13.4 ps) than individual ZnTPP NSs. This work provides a strategy to construct the organic nanostructures for photocatalytic CO2RR to multi-electron products.

Construction of Cobalt Porphyrin-Modified Cu2 O Nanowire Array as a Tandem Electrocatalyst for Enhanced CO2 Reduction to C2 Products.

Here, the molecule-modified Cu-based array is first constructed as the self-supporting tandem catalyst for electrocatalytic CO2 reduction reaction (CO2 RR) to C2 products. The modification of cuprous oxide nanowire array on copper mesh (Cu2 O@CM) with cobalt(II) tetraphenylporphyrin (CoTPP) molecules is achieved via a simple liquid phase method. The systematical characterizations confirm that the formation of axial coordinated Co-O-Cu bond between Cu2 O and CoTPP can significantly promote the dispersion of CoTPP molecules on Cu2 O and the electrical properties of CoTPP-Cu2 O@CM heterojunction array. Consequently, as compared to Cu2 O@CM array, the optimized CoTPP-Cu2 O@CM sample as electrocatalyst can realize the 2.08-fold C2 Faraday efficiency (73.2% vs 35.2%) and the 2.54-fold current density (-52.9 vs -20.8 mA cm-2 ) at -1.1 V versus RHE in an H-cell. The comprehensive performance is superior to most of the reported Cu-based materials in the H-cell. Further study reveals that the CoTPP adsorption on Cu2 O can restrain the hydrogen evolution reaction, improve the coverage of * CO intermediate, and maintain the existence of Cu(I) at low potential.

Processing mechanism synergizing surface and intercalation pseudocapacitance engineering fast-charging Li-based anode materials.

Pseudocapacitive material can achieve rapid charge and discharge response. In this study, a vanadium-based conductive network hydrate (Na0.13Mg0.02)V2O5·0.98H2O (NMVO) was designed. The Na+ and Mg2+ in NMVO are sandwiched between two layers of vacancy-ordered prisms and monoclinic nanonetwork V3O7 (VO2:V2O5 = 1:1) to form a conductive network with a layer spacing of up to 11.67 Å, this structure facilitates rapid interlayer diffusion of cations and enhanced conductivity. Reduction-NMVO (r-NMVO) with hierarchical heterostructures was prepared via an in-situ electrochemical process to generate interlayer vanadium-based active sites (LiV3O8, LiV2O5, Na3V3O8, MgVO3) with multi-electron reaction, which enhanced the generation of surface redox pseudocapacitance. The interlayer heterostructure is integrated with the core of the precursor V3O7 to form an active site-rich conductive network with strong pulse impact resistance, which promotes the generation of intercalated pseudocapacitance and increases the cycle stability of the electrode. This intercalation-surface redox pseudocapacitive mechanism was confirmed by first-principles, in-situ, and ex-situ characterization analysis. The r-NMVO|Li battery still maintains a capacity of 95.5 % after 65,500 cycles at a current density of 50 A g-1. These results contribute directly to the realization of stable, fast charge and discharge material design.

Highly efficient electrochemical reforming of CH4/CO2 in a solid oxide electrolyser.

Reforming CH4 into syngas using CO2 remains a fundamental challenge due to carbon deposition and nanocatalyst instability. We, for the first time, demonstrate highly efficient electrochemical reforming of CH4/CO2 to produce syngas in a solid oxide electrolyser with CO2 electrolysis in the cathode and CH4 oxidation in the anode. In situ exsolution of an anchored metal/oxide interface on perovskite electrode delivers remarkably enhanced coking resistance and catalyst stability. In situ Fourier transform infrared characterizations combined with first principle calculations disclose the interface activation of CO2 at a transition state between a CO2 molecule and a carbonate ion. Carbon removal at the interfaces is highly favorable with electrochemically provided oxygen species, even in the presence of H2 or H2O. This novel strategy provides optimal performance with no obvious degradation after 300 hours of high-temperature operation and 10 redox cycles, suggesting a reliable process for conversion of CH4 into syngas using CO2.

Sensitive fluorescence biosensor for folate receptor based on terminal protection of small-molecule-linked DNA.

Based on the specific folic acid-folate receptor (FA-FR) interaction, macromolecular FR can bind with FA-linked DNA-small molecule chimeras, which can prevent enzymolysis by exonuclease III (Exo III), enabling a novel fluorescence biosensor for FR to be developed using quinaldine red as a G-quadruplex-binding probe.

Logic gates for multiplexed analysis of Hg2+ and Ag+.

The design of devices with multiple functions, simple handling procedures and sufficient sensitivity has drawn great interests in the field of analysis. Metal-nucleotide based pairs, such as T-Hg(2+)-T and C-Ag(+)-C complexes accompanied by SYBR Green I (SG), are used to selectively bind duplex-strand DNA by observing a bright fluorescence signal in this work, thus yielding a simple method for the rapid detection of Hg(2+) and Ag(+) without a complex labeling process. Based on this principle, 'OR' and 'AND' logic gates for the multiplexed analysis of Hg(2+) and Ag(+) were developed, and their practical application for the detection of Hg(2+) and Ag(+) in drinking water was reported.