ACS Energy Letters 最新文献

While catalytic performances are usually sensitive to catalyst surface structures at the nanoscale and atomic scale, crucial factors affecting species transport at the mesoscale are often overlooked. Here we reveal the role of interparticle distance in tuning product selectivity in CO electrolysis at industrially relevant current densities using model Cu nanoparticle gas diffusion electrodes with tunable average interparticle distances. Increasing the average interparticle distance of Cu nanoparticles remarkably increases the selectivity toward acetate, a specific multicarbon product. Experimental and numerical calculation results indicate that a larger interparticle distance increases the local pH near Cu nanoparticles and the local CO concentration owing to weakened interparticle CO diffusion at the mesoscale. By coupling external reaction conditions, the maximum acetate Faradaic efficiency and partial current density reach 77.5% and 705 mA cm^–2, respectively. Our findings illustrate the importance of interparticle distance as a mesoscopic descriptor for selectivity control in complex catalytic reactions under industrially relevant conditions.

Understanding photophysical processes in lead halide perovskites is an important aspect of optimizing the performance of optoelectronic devices. The determination of exact charge carrier extraction rate constants remains elusive, as there is a large and persistent discrepancy in the reported absolute values. In this review, we concentrate on experimental procedures adopted in the literature to obtain kinetic estimates of charge transfer processes and limitations imposed by the spectroscopy technique employed. Time-resolved techniques (e.g., transient absorption–reflection and time-resolved photoluminescence spectroscopy) are commonly employed to probe charge transfer at perovskite/transport layer interfaces. The variation in sample preparation and measurement conditions can produce a wide dispersion of the measured kinetic parameters. The selected time window and the kinetic fitting model employed introduce additional uncertainty. We discuss here evaluation strategies that rely on multiexponential fitting protocols (regular or stretched) and show how the dispersion in the reported values for carrier transfer rate constants can be resolved.

Perovskite solar cells (PSCs) show promise for future photovoltaic technology. However, it faces challenges in terms of environmental stability. To address this, researchers have proposed nanomaterials such as perovskite quantum dots (QDs) to passivate the perovskite interfaces and enhance their stability. We explore the halide exchange reaction at the heterojunction between QDs and bulk (3D) perovskites using in situ photoluminescence. By determining the activation energy for the interfacial bromide-to-iodide exchange, we find that it is effective in passivating the 3D surface defects and grain boundaries. When applied in solar cells, QDs have energy level realignment, improving hole extraction and blocking electron transfer, which reduces bimolecular charge carrier recombination, thus increasing efficiency. The interfacial halide composition remains stable under thermal stress, and the QDs’ ligand hydrophobicity was found to prevent moisture permeation within the perovskite films. Thus, strategically incorporating QDs enhances photovoltaic performance and has the potential to mitigate moisture and thermal-induced degradation.

Dendritic zinc electrodeposition-mediated short-circuiting is the predominant failure mode reported for aqueous zinc batteries. While zinc corrosion is implicated in poor Coulombic efficiency, corrosion-mediated zinc depletion is rarely blamed for cell failure. This study critically examines corrosion-mediated zinc depletion and associated cell failure, considering cell configuration and key parameters: zinc reserve and electrolyte to capacity ratio. Surprisingly, zinc depletion emerges as a more significant issue than previously thought, even with a thin separator that can expedite short circuits. The second zinc electrode in the symmetric cell setup acts as a zinc reserve, inflating the battery’s lifespan. Conversely, the asymmetric setup accurately simulates zinc-starved conditions, providing a precise evaluation of zinc depletion, consistent with full-cell cycling results. It is demonstrated that for a threshold electrolyte content the full-cell capacity decay primarily results from zinc corrosion and loss, and cell revival is achievable by replacing the spent anode with a fresh one.

The photoelectrochemical (PEC) water oxidation reaction on hematite photoanodes poses challenges, notably the limited hole diffusion length and poor electrical properties. This study addresses these issues by creating a highly porous structure through the Kirkendall effect at the interface of the overlayer and hematite precursor. By fabricating branched hematite precursors, we produced a highly nanoporous structure with an average strut diameter below 10 nm between pores. Coupled with morphological engineering, doping from the overlayer enhances the electrical properties of hematite, and the selection of an appropriate dopant (overlayer) was determined through density functional theory. The optimized photoanode with a NiFe(OH)_x cocatalyst displayed a maximum photocurrent density of 5.1 mA cm^–2 at 1.23 V_RHE, a 3.2-fold increase compared to the reference. The enhancement results from the nanoporous structure combined with optimal doping conditions, representing a significant step in improving the low PEC performance of hematite-based photoanodes.

Organic solar cells (OSCs) have emerged as promising energy harvesters owing to their outstanding optoelectronic properties, approaching a maximum power conversion efficiency of over 19%. However, single-junction OSCs have limitations in improving efficiency owing to transmission and thermalization losses. To alleviate these drawbacks, a tandem configuration was devised, involving the stacking of two subcells to absorb a broad solar spectrum and minimize transmission and thermalization losses. This tandem strategy is not limited to organic/organic-based systems but extends to organic/perovskite-, organic/colloidal quantum dot (CQD)-, and organic/amorphous silicon (a-Si)-based tandem solar cells (TSCs). This Review commences with a brief overview of developments in organic photoabsorbers and introduces the general concepts of TSCs. Then, we summarize recent research endeavors for organic/organic-, organic/perovskite-, organic/CQD-, and organic/a-Si-based hybrid TSCs. Lastly, the Review concludes by offering insights and prospects for enhancing the performance of organic-based hybrid TSCs by ≥25%.

Rechargeable metal–sulfur batteries with low-cost, soil-rich elemental sulfur as the cathode have attracted considerable attention, as they are crucial for working at room temperature due to their high energy density, high output efficiency, and convenient operation. However, the performance is limited by the low utilization of sulfur, severe volume expansion, and shuttle effect of polysulfides. To address these issues, a key strategy is to design carbon materials with excellent conductivity and high specific surface area, preferably with high chemical affinity and high sulfur loading. In this Review, the fundamentals of room-temperature metal–sulfur batteries and the rational design of carbon sulfur carriers are presented, going into the relationship between carbon sulfur hosts and battery performance. Recent developments are highlighted along with potential directions for future research. This comprehensive review aims to provide guidelines for the design of carbonaceous sulfur hosts and promising methods for the development of high-performance room-temperature metal–sulfur battery systems.

Hydrogen production through anion-exchange membrane water electrolyzers (AEMWEs) offers cost advantages over proton-exchange membrane counterparts, mainly due to the good oxygen evolution reaction (OER) activity of platinum-group-metal-free catalysts in alkaline environments. However, the electrochemical oxidation of ionomers at the OER catalyst interface can decrease the local electrode pH, which limits AEMWE performance. Various strategies at the single-cell-level have been explored to address this issue. This work reviews the current understanding of electrochemical ionomer oxidation and strategies to mitigate it, providing our perspective on each approach. Our analysis highlights the competitive adsorption strategy as particularly promising for mitigating ionomer oxidation. This Perspective also outlines future directions for advancing high-performance alkaline AEMWEs and other energy devices using hydrocarbon ionomers.