Heterostructure engineering plays a vital role in regulating the material interface, thus boosting the electron transportation pathway in advanced catalysis. Herein, a novel Bi2O3/BiO2 heterojunction catalyst was synthesized via a molten alkali-assisted dealumination strategy and exhibited rich structural dynamics for an electrocatalytic CO2 reduction reaction (ECO2RR). By coupling in situ X-ray diffraction and Raman spectroscopy measurements, we found that the as-synthesized Bi2O3/BiO2 heterostructure can be transformed into a novel Bi/BiO2 Mott–Schottky heterostructure, leading to enhanced adsorption performance for CO2 and *OCHO intermediates. Consequently, high selectivity toward formate larger than 95% was rendered in a wide potential window along with an optimum partial current density of −111.42 mA cm–2 that benchmarked with the state-of-the-art Bi-based ECO2RR catalysts. This work reports the construction and fruitful structural dynamic insights of a novel heterojunction electrocatalyst for ECO2RR, which paves the way for the rational design of efficient heterojunction electrocatalysts for ECO2RR and beyond.
The M‐to‐N2 π‐backdonation weakens the triple bond of N2 and shall promote the sluggish electrochemical nitrogen reduction reaction (ENRR). By using weak σ‐ and π‐donating graphdiyne (GDY) as a supporting material, herein, a versatile approach is described to stabilize low‐valence metal single atoms (SA) on GDY (M SA/GDY; M = Cr, Mo, W, Mn, and Re). Under the rigorous ENRR protocol, an activity trend of Re SA/GDY > Mo SA/GDY > Cr SA/GDY > W SA/GDY >> Mn SA/GDY (no activity) is delivered. Theoretical calculations reveal that the strong M‐to‐N2 π‐backdonation of Re SA/GDY renders a low energy requirement of +0.39 eV for the reductive hydrogenation of *N2 to *NNH, which is considered as the bottleneck of ENRR. A novel NH3 desorption mechanism through N2 or H2O aided ligand exchange mechanism is proposed to facilitate the NH3 desorption from Re SA/GDY with a low energy input of +0.83 eV for the distal and mix pathways. This study expands the scope of low‐valance SA with boosted π‐backdonation capacity and offers new mechanistic insights for ENRR.
Ultrathin two-dimensional (2D) metal oxyhalides exhibit outstanding photocatalytic properties with unique electronic and interfacial structures. Compared with monometallic oxyhalides, bimetallic oxyhalides are less explored. In this work, we have developed a novel top-down wet-chemistry desalination approach to remove the alkali-halide salt layer within the complicated precursor bulk structural matrix Pb0.6Bi1.4Cs0.6O2Cl2, and successfully fabricate a new 2D ultrathin bimetallic oxyhalide Pb0.6Bi1.4O2Cl1.4. The unlocked larger surface area, rich bimetallic active sites, and faster carrier dynamics within Pb0.6Bi1.4O2Cl1.4 layers significantly enhance the photocatalytic efficiency for atmospheric CO2 reduction. It outperforms the corresponding parental matrix phase and other state-of-the-art bismuth-based monometallic oxyhalides photocatalysts. This work reports a top-down desalination strategy to engineering ultrathin bimetallic 2D material for photocatalytic atmospheric CO2 reduction, which sheds light on further constructing other ultrathin 2D catalysts for environmental and energy applications from similar complicate structure matrixes.
Ultrathin two-dimensional (2D) nanosheets with efficient light-driven proton reduction activity were obtained through the exfoliation of novel metal–organic frameworks (MOF), which were synthesized by using a bis(4′-carboxy-2,2′:6′,2″-terpyridine) ruthenium complex as a linker and 3d transition-metal (Mn, Co, Ni, and Zn) anions as nodes. The nanosheet of the Ni2+ node exhibits a photocatalytic hydrogen evolution rate of 923 ± 40 μmol g–1 h–1 at pH = 4.0, without the presence of any cocatalyst or cosensitizer. A combined experimental and theoretical study suggests a reductive quenched pathway for the photocatalytic hydrogen evolution by the nanosheet. The transition-metal nodes at the edge of the nanosheets are proposed as the active sites. Density functional theory (DFT) calculations attributed the different catalytic activities of the nanosheets to the discrepancy of H adsorption free energy at various transition-metal nodes.
Iron-based nanosized ecomaterials for efficient Cr(VI) removal are of great interest to environmental chemists. Herein, inspired by the "mixed redox-couple" cations involved in the crystal structure and the quantum confinement effects resulting from the particle size, a novel type of iron-based ecomaterial, semiconducting chalcopyrite quantum dots (QDs), was developed and used for Cr(VI) removal. A high removal capacity up to 720 mg/g was achieved under optimal pH conditions, which is superior to those of the state-ofthe-art nanomaterials for Cr(VI) removal. The mechanism of Cr(VI) removal was elucidated down to an atomic scale by combining comprehensive characterization techniques with adsorption kinetic experiments and DFT calculations. The experimental results revealed that the material was a good electron donor semiconductor attributed to the existence of "mixed redox couple of Cu(I)-S-Fe(III)" in the crystal structure. With the size-dependent quantum confinement effect and the high surface area, the semiconducting chalcopyrite QDs could effectively remove Cr(VI) from aqueous solution through a syngenetic photocatalytic reduction and adsorption mechanism. This study not only reports the design histogram of the iron-based CuFeS 2 QD ecomaterial for efficient Cr(VI) removal but also paves the way for understanding the atomic-scale mechanism behind the syngenetic effects of using the QD semiconducting material for Cr(VI) removal.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.