EcoEnergy最新文献

Covalent organic frameworks (COFs) have been widely employed as electrocatalysts for oxygen reduction reaction (ORR) due to their diverse and tunable skeletons and pores. However, their electrocatalytic activity was limited due to the lack of highly active catalytic sites. In this work, we have first immobilized palladium nanoparticles (NPs) into the crystal, porous, and stable imide-linked COF for ORR. The newly designed COF had pyridine linkers with imide-linkages in the frameworks serving as the binding sites to anchor Pd sites, and the high surface area and open pore channels provide fast mass transport pathway to the active Pd sites, which contributed highly active performance in ORR. And the designed catalyst delivered onset potential and the half-wave potential of COF-Pd of 0.97 and 0.83 V, with a limited current density of 6.1 mA cm⁻², respectively. This work provides us insights into developing high crystalline COFs with metal NPs in electrocatalytic systems.

The liquid-phase-assisted grain growth (LGG) process is a promising strategy to fabricate large-grain pure sulfide Cu₂ZnSnS₄ (CZTS) layers that span the absorber thickness and improve the carrier collection efficiency in photovoltaic devices. Li doping is an effective route to promote such LGG process of Cu₂ZnSn(S,Se)₄ (CZTSSe) as it can provide liquid Li-Se phase facilitating the growth of large-grain CZTSSe. However, the detailed function of the added Li in grain growth has rarely been investigated in both CZTS and CZTSSe, as the reported in situ, and pre-deposition doping strategies usually suffer from substantial Li losses during the spin-coating process and/or the high-temperature sulfurization process. Herein, by monitoring the temperature-dependent Li loss during the sulfurization process, we demonstrate that a small proportion of the added Li can remain at the CZTS film from the early sulfurization stage and provide Li-S flux to promote the LGG process. An encouraging efficiency of 10.53%, with a remarkably high short-circuit current density of 22.6 mA/cm² and open-circuit voltage of 0.744 V, is achieved by a significantly enlarged grain size of 3 μm with Li addition. This work could enhance the knowledge of employing Li-S as flux for growing large-grain chalcogenide absorbers for high performance devices with better carrier transport.

The energy density of Lithium-ion batteries (LiBs) fails to keep pace with the growing demand for long-driving range EVs. Developing novel anode materials with high specific capacities is one of the most effective ways to increase the energy density of LiBs. Herein, a series of Cu and Co binary-transition metal glycerolates (labeled as Cu_xCo_y/G) were prepared as the anodes for LiBs. It was observed that Cu_xCo_y/G exhibited a distinctive yolk-shell architecture, which significantly differed from the solid spherical structure of Cu/G and Co/G counterparts. X-ray powder diffraction and Scanning electron microscope studies suggested that Cu element existed as Cu₂₊₁O in Cu_xCo_y/G, and the Co element was in the form of amorphous glycerolates. Electrochemical studies showed that Cu_0.4Co₁/G delivered a high capacity over 1000 mAh g⁻¹ at the first discharge, and it exhibited the most stable cycling performance over 200 cycles. Mechanism study suggested both Cu and Co elements contributed to lithium storage capacities in Cu_xCo_y/G at the initial discharging process. Experimental results revealed that Co exhibited reversible capacity while Cu element was reduced to metallic Cu which contributed to the electronic conductivity, rendering Cu_0.4Co₁/G exhibited a better long-term cycling stability than Co/G. This work explored a new type of anode material with high specific capacity for LiBs, paving the way to high energy density LiBs.

Developing efficient electrocatalysts for water electrolysis is critical for sustainable hydrogen energy development. For enhancing the catalytic performance of metal catalysts, dual doping has attracted enormous interest for its high effectiveness and facile realization. Dual doping is effective for tuning the electronic properties, enhancing the electrical conductivity, populating active sites, and improving the stability of metal catalysts. In this review, recent developments in cation–cation, cation–anion, and anion–anion dual-doped catalysts for water splitting are comprehensively summarized and discussed. An emphasis is put on illustrating how dual doping regulates the external and internal properties and boosts the catalytic performance of catalysts. Additionally, perspectives are pointed out to guide future research on engineering high-performance heteroatom-doped electrocatalysts.

Single-atom-based catalysts are intriguing electrocatalytic platforms that combine the advantages of molecular catalysts and conductive carbon-based materials. In this work, hybrids (Co-NrGO-1 and Co-NrGO-2) were generated by wet-reactions between organometallic complexes (Co(CH₃COO)₂ and Co[CH₃(CH₂)₃CH(C₂H₅)COO]₂, respectively) and N-doped reduced graphene oxide at 25°C. Various characterizations revealed the formation of atomically dispersed Co(O)₄(N) species in Co-NrGO-2. Density functional theory (DFT) calculations explained the effect of the aliphatic C7 group in Co2 on the formation processes. The Co-NrGO-2 hybrid showed excellent catalytic performance, such as onset (0.94 V) and half-wave (0.83 V) potentials, for electrochemical oxygen reduction reaction (ORR). Co-NrGO-2 outperformed Co-NrGO-1, which was explained by more back donation to the antibonding orbitals of O₂ from electron-rich aliphatic groups. DFT calculations support this feature, with mechanistic investigations showing favored ORR reactions and facile breakage of double bonds in O₂.

Electrocatalytic dehalogenation technology is a promising approach for the synthesis of chemicals (such as pesticides and pharmaceutical intermediates) and the disposal of halogenated organic pollutants. Compared with the traditional chemical reduction technology, the electrocatalytic reduction dehalogenation method has the advantages of high efficiency, controllable operation, and reduced secondary pollution. This review systematically consolidates the recent advances in the electrocatalytic dehalogenation in the application of organic synthesis and environmental degradation, focusing on the involved mechanisms, and influences factors (e.g., electrocatalysts, solution environment, and reaction conditions) on the performance of electrocatalytic dehalogenation. Furthermore, the latest characterization and analytical methods and the industrial application of electrocatalytic dehalogenation technology are summarized. Lastly, the existing challenges and perspectives are proposed for efficient electrocatalytic dehalogenation.

Metal suboxides have emerged as a class of promising candidates for many electrocatalytic applications owing to their enhanced electrical conductivity and chemical activities. In this review, we have summarized the recent progress of metal suboxides. We have firstly introduced the discovery of metal suboxides, and their categories according to element tables. Then various metal suboxides synthetic methods have been systematically illustrated involving solid-state synthesis, high-temperature synthesis, low-temperature synthesis and plasma-driven synthetic methods, etc. In addition, their applications have been demonstrated in the field of water, carbon and nitrogen cycle-based energy catalysis technologies involving electrochemical hydrogen evolution reaction, oxygen evolution reaction, oxygen reduction reaction, carbon dioxide reduction, urea oxidation reaction, methanol oxidation reaction, nitrogen reduction reaction and nitrate reduction reaction, etc. Finally, we make a brief conclusion about the developments of metal suboxides, giving an outlook for future research challenges. These insights are expected to hold promise for developing metal suboxide catalysts toward practical applications.

Layered double hydroxides (LDHs)-based photocatalysts have generated widespread interest owing to their great potential for solving both energy and environmental issues through directly converting nonconsumable solar energy. Numerous methods have been investigated and analyzed in recent years to promote the photocatalytic efficiency of LDHs. Z-scheme heterojunction that mimics the artificial photosynthesis is employed in photocatalysis owing to the outstanding advantages, such as high quantum efficiency, separation of redox sites, and low recombination of photocarriers. Herein, various LDHs-based Z-scheme heterojunction photocatalysts are briefly reviewed. Z-scheme heterojunction associated with LDHs-based materials exhibit high photocatalysis performance, and these types of hybrids are applied in photocatalytic H₂O splitting, CO₂ reduction, and pollution degradation, which are introduced and summarized in detail. In the end, a brief conclusion focused on future challenges and expectations of LDH-based Z-scheme photocatalytic system is presented. We expect that more advances for LDH-based Z-scheme photocatalyst can be achieved in the field of photocatalysis in the coming days.

All-solid-state lithium batteries with Li metal anodes and solid-state electrolytes (SSEs) can achieve higher energy density and enhanced safety compared to the current liquid-based Li-ion batteries. Among several SSEs, Li₇La₃Zr₂O₁₂ (LLZO) has attracted attention due to its high Li⁺ ion conductivity (∼10⁻³ S cm⁻¹ at room temperature for Ga-doped LLZO) and good stability in ambient air. However, the challenges of Li penetration and the chemical instability against Li are the primary obstacles to its practical application. This study investigates the effects of the grain size and electronic conductivity of Ga-doped LLZO on the critical current density (CCD). Using samples with similar interfacial impedances between Ga-doped LLZO and Li, we demonstrate that a decrease in the grain size of Ga-doped LLZO lowers the electronic conductivity, leading to a higher CCD. Furthermore, although a previous study suggests that Ga-doped LLZO might be unsuitable for direct contact with Li, the chemical stability against Li is enhanced in a more compact pellet prepared at a higher cold-pressing pressure. These results underscore the significance of the sintering conditions and pellet pressing pressure in the synthesis of Ga-doped LLZO since they ultimately affect the electrochemical and chemical stabilities of the Ga-doped LLZO solid electrolyte with a Li-metal anode.

Electrochemical CO₂ reduction reaction (CO₂RR) has attracted much attention in the last decade, owing to its unique advantages such as operation at ambient conditions, coupling with renewable electricity, and producing a wide range of products and commodities. The majority of CO₂RR studies are focused on pure CO₂ as feed, while in real CO₂ waste streams, such as flue gas or biogas, CO₂ concentration does not exceed 40%. Therefore, the economic feasibility of CO₂RR and its carbon footprint are greatly limited by the CO₂ purification steps before electrolysis ($70–100 per ton of CO₂ for CO₂/N₂ separation). In recent years, studies have exhibited the importance of this matter by integrating CO₂ capture and electroreduction in a single unit. Mostly, CO₂ capture solutions as electrolytes have been under attention, and promising results have been achieved to significantly improve the overall economy of CO₂RR. The focus on CO₂ capture-electroreduction integration can go beyond the solution/electrolyte-based CO₂ capture (e.g., amine solutions and ionic liquids) and other processes such as solid adsorption and membrane-based processes, as more efficient options, can be potentially integrated with CO₂ electroreduction in the gas-diffusion electrode design. This article aims to review the recent efforts in integrating capture and electroreduction of CO₂ and provides new perspectives in material selection and electrode design for membrane- and adsorption-based CO₂ capture-reduction integration, in addition to the analysis of the economic feasibility of this integration.