Applied Catalysis B: Environmental最新文献

Ethylene production by CO₂ reduction is sluggish because the repulsive dipole-dipole interaction and 12 proton-coupled electron-transfer steps consecutively. Amorphous structured photocatalysts possess few grain boundaries and abundant unsaturated sites, accelerating the reaction efficiency from the angle of dynamics and thermodynamics, which still not yet be used in PCR to C₂ products currently. Herein, an amorphous Cu_xCoS_y composed of the minority crystalline CuCo₂S₄ is fabricated to realize an excellent C₂H₄ selectivity in terms of R_electron (94.9%). Unsaturated Co and S play the key roles in the improved efficiency of C₂H₄ generation. C-C coupling is achieved via shortening Co-S bonds distance, and *CO-*CO coupling barrier is decreased by more electrons accumulated on unsaturated S. Water is adsorbed on Co adjacent to S and provide protons for *COCO to form *CH₂ = C. This work paves a new way for broadening the efficient of C₂H₄ photocatalytic evolution using amorphous photocatalyst.

Owing to the elusive pathways of methanol oxidation reaction (MOR) and the lack of applicable catalysts, the selective electro-oxidation of methanol to formate remains a challenging topic. Herein, we present a chromium-doping strategy to promote the MOR performance of α-Ni(OH)₂ nanosheets with a high selectivity towards formate generation. Taking chromium-doped α-Ni(OH)₂ nanosheets as an example, we further highlight the role of doping atoms in MOR by combining theoretical calculations with experimental measurements. It reveals that chromium doping can not only enhance the conductivity of α-Ni(OH)₂ nanosheets, but also endow the catalyst with optimized kinetics for electroactive NiOOH formation and methanol absorption, thus resulting in a remarkable MOR current density of 141 mA cm⁻² at 0.50 V vs. Ag/AgCl with a faradaic efficiency of 92.1% for formate. Furthermore, in situ infrared spectroscopy demonstrates that methanol is selectively oxidized to formate without further oxidation to CO₂ over chromium-doped α‑Ni(OH)₂ nanosheets in alkaline media.

A highly efficient Si-doped ZnAl-LDH (denoted as Si-ZnAl-LDH nanosheet) catalyst that is derived from large-area chemical exfoliation for photoelectrocatalytic water splitting. The formation of amorphous Si-ZnAl-LDH nanosheets through chemical exfoliation or layer engineering leads to much more accessible surfaces that originally are not accessible in highly crystalline ZnAl-LDH sheets. The incorporation of Si to highly exfoliated ZnAl-LDH nanosheets generates more oxygen vacancies, increases the number of active sites, redistributes the local charge density of the active centers and effectively suppresses the recombination of the generated electron-hole pairs. Specifically, the overpotential of HER and OER for Si-ZnAl-LDH nanosheet is 108 mV and 260 mV, respectively, at current density of 10 mA cm⁻² under light-assisted conditions. Total applied voltage is 1.673 V for water splitting in a full cell. This work provides a novel chemical exfoliation or layer-engineering strategy for the synthesis of scalable and cost-effective LDH nanosheets with efficient photoelectric response.

As atmospheric carbon dioxide (CO₂) levels surge due to human activities, addressing this global crisis is paramount. This article delves into the realm of photoelectrochemical (PEC) CO₂ reduction, a promising solution that combines solar energy conversion and electrochemical processes to transform CO₂ into clean energy fuels. The primary focus of this article lies in the cutting-edge unbiased PEC tandem configurations, specifically reviewing recent breakthroughs in coupling PEC CO₂ reduction with the oxygen evolution reaction through water oxidation. By consolidating the latest insights and knowledge, this comprehensive review guides readers through the evolving landscape of advanced PEC technologies. Furthermore, it provides insights into prospective developments in this evolving field, shedding light on the paths toward sustainable energy solutions and climate mitigation.

Searching substrate materials having inherent photocatalytic activity and interaction with single atoms remains challenge. Herein, amorphous Al₂O₃ containing penta-coordinated aluminum (Al^V) species is synthesized using the solvothermal method and the Au single atom is anchored by Al^V via the self-reduction strategy. The Al-O bond energy is weakened by introducing amorphous components, which benefits the release of oxygen atoms and the resultant change of Al coordination environment to a Al^V species. The electron transfer between Al^V and Au stabilizes the Au single atom. The introduction of the Au single atom occupying the position of O vacancy and anchored by Al^V strengthened the chemical absorption abilities for CO_2, lowered the energy barrier of CO generation and promoted the charge separation efficiency. The CO generation rate of the Au single atom anchored obtains extraordinary promotion in comparison with pristine Al₂O₃, resulting in an approximately 6-fold enhancement and 98% product CO selectivity.

In this work, an efficient CO₂ photoreduction catalyst based on Co₃O₄/ZnIn₂S₄ hollow hetero-nanocubes is precisely constructed via an in-situ transformation of cobalt-organic framework followed by a solvothermal reaction. Comprehensive in-situ spectroscopic analyses and theoretical calculations have revealed that the critical interfacial electron interactions (IEIs) effects on both photoactivity evolution and selectivity modulation in the Co₃O₄/ZnIn₂S₄ hetero-structure. As the content of ZnIn₂S₄ increases in the hetero-structure, the photoactivity exhibits a volcano-like evolution profile but the CH₄ selectivity reduces monotonously. The improved photoactivity is attributed to the IEIs-promoted charge separation as well as the specific-surface-area effect in terms of electron unitization rate, and the electronic structure of Co₃O₄ is tuned and the energy barrier for the key reaction intermediate *CHO is reduced, leading to improved CH₄ selection in comparison with bare Co₃O₄. The IEIs-mediated production selectivity is further verified by a Co₃O₄/CeO₂ heterojunction, indicating a certain universality of the IEI effect.

Here, we demonstrate an integrated fluidic sequential electrochemical system for effective water decontamination. The system consists of a Ti mesh anode deposited with nanoscale IrO₂ and a CNT filter functionalized with nanoconfined Fe₂O₃. By conducting anodic oxygen evolution reaction (OER) and 2e^– oxygen reduction reaction (ORR) sequential electrolysis, our system enables sustainable O₂ generation at the anode, followed by transformation of O₂ into H₂O₂ at the cathode, which then led to the production of ¹O₂ in the presence of nanoconfined Fe₂O₃. No chemical inputs were needed nor side products occurred during the whole sequential electrochemical processes. The effectiveness of the system was evaluated using tetracycline as a model emerging contaminant. Recirculating at 3 mL min^–1, the system exhibited negligible iron and iridium leaching (≤0.01 mg L^–1) and high tetracycline degradation efficiency (≥95%). Such excellent efficacy can be maintained across a wide pH range and in complicated water matrices.

Two-dimensional (2D)-interface engineering for designing effective electron-rich catalyst center is pivotal in manipulating the catalytic behaviors and activity, but still challenging. Here, we’ve successfully twisted the surfaces of the 2D layered FeOCl, fulfilling the targeted fine-tuning of its Fe sites. The obtained new catalyst can boost peroxymonosulfate activation for reactive species with much lower energy barriers and efficiently oxidized target organic with almost 41 orders of magnitude faster reaction kinetics than pristine FeOCl. The increased degree of freedom of electron around Fe site has been identified as the key driver. The distorted geometry structure around Fe has led to an increased polarization of charge distribution, associating with less symmetric electron valence cloud and higher electron mobility. Thus, the twisted surfaces enable a much enhanced interfacial charge transfer between Fe site and the electron-deficient peroxymonosulfate. This work highlights the concept of twisted surface construction toward efficient advanced oxidation catalyst design.

Oxygen vacancy (V_O) on semiconductor photoanode plays an important role in enhancing photoelectrochemical water oxidation performances. Nonetheless, there is still a lack of definitive elucidation regarding the structural changes and their impact on charge transport during the oxygen evolution reaction (OER). Herein, oxygen vacancies were rationally introduced on WO₃ nanoflake photoanodes via Ar-plasma engraving, resulting in a threefold increase in the photocurrent density of 2.76 mA cm⁻² at 1.23 V_RHE under AM 1.5 G solar irradiation compared to the pristine WO₃ photoanode. Comprehensive experiments and theoretical calculations reveal that the self-healing process of surface oxygen vacancies on WO₃ photoanodes should be more easily achieved by capturing oxygen atoms from adsorbed H₂O molecules. However, some survived oxygen vacancies in the subsurface could effectively increase the charge carrier density and provide the additional driving force to accelerate the interfacial charge transport, leading to enhanced photoelectrochemical (PEC) activities. More importantly, the oxygen vacancy self-healing on metal-oxide semiconductors is a universal phenomenon, which might bring new insights for design and construction of highly efficient photoanodes for PEC water oxidation.