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Electroreduction of carbon dioxide into value-added fuels or chemicals using renewable energy helps to effectively reduce carbon dioxide emission and alleviate the greenhouse effect while storing intermittent energies. Due to the existing infrastructure of global natural gas utilization and distribution, methane produced in such a green route attracts wide interests. However, limited success has been witnessed in the practical application of catalysts imparting satisfactory methane activity and selectivity. Herein, we report the fabrication of an atomically dispersed Co−Cu alloy through the reconstruction of trace-Co doped Cu metal-organic framework. This catalyst exhibits a methane Faradaic efficiency of 60% ± 1% with the corresponding partial current density of 303 ± 5 mA·cm−2. Operando X-ray adsorption spectroscopy and attenuated-total-reflection surface enhanced infrared spectroscopy unravel that the introduction of atomically dispersed Co in Cu favors *CO protonation via enhancing surface water activation, and suppresses C−C coupling by reducing *CO coverage, thereby leading to high methane selectivity. [ABSTRACT FROM AUTHOR]

Sulfurized polyacrylonitrile (SPAN) is attractive as one of the most promising cathode candidates for commercial lithium–sulfur (Li–S) batteries due to its outstanding capacity reversibility and structural stability. However, the limited sulfur content of ∼40 wt% in the composite hinders its practical applications owing to insufficient areal/volumetric energy density, especially when used as flexible cathodes for wearable energy storage devices. Here, we report an ultrathin and condensed SPAN film synthesized via the in situ growth of ZIF-67 on electrospun fibers composed of PAN and CNTs, followed by a vulcanization process to generate surface-anchored CoS2 that effectively suppresses fiber swelling and film thickening. Simultaneously, conductive CoS2 helps expedite the redox kinetics of sulfur conversion for achieving high-performance Li–S cells with much improved areal capacity. This study refreshes current performance of SPAN cells with an ultrahigh initial areal capacity of 8.1 mA h cm−2 at a sulfur loading of up to 5.9 mg cm−2, as well as a superior capacity of 1322 mA h g−1 in the prototype pouch cell, demonstrating great prospects of the employed protocol for realizing flexible Li–S batteries with high energy density. [ABSTRACT FROM AUTHOR]

Artificial photocatalytic CO 2 reduction (CO 2 R) holds great promise to directly store solar energy into chemical bonds. The slow charge and mass transfer kinetics at the triphasic solid-liquid-gas interface calls for the rational design of heterogeneous photocatalysts concertedly boosting interfacial charge transfer, local CO 2 concentration, and exposure of active sites. To meet these requirements, in this study heterostructures of CdS/MOL (MOL = metal-organic layer) furnishing different redox Co sites are fabricated for CO 2 R photocatalysts. It is found that the coordination environment of Co is key to photocatalytic activity. The best catalyst ensemble comprising ligand-chelated Co 2+ with the bipyridine electron mediator demonstrates a high CO yield rate of 1523 µmol h -1 g cat -1 , selectivity of 95.8% and TON of 1462.4, which are ranked among the best seen in literature. Comprehensive photochemical and electroanalytical characterizations attribute the high CO 2 R performance to the improved photocarrier separation and charge kinetics originated from the proper energy band alignment and coordination chemistry. This work highlights the construction of 2D heterostructures and modulation of transition metal coordination to expedite the charge kinetics in photocatalytic CO 2 reduction., (© 2024 Wiley‐VCH GmbH.)

Implementing the synergistic effects between the metal and the ligand has successfully streamlined the energetics for CO 2 activation and gained high catalytic activities, establishing the important breakthroughs in photocatalytic CO 2 reduction. Herein, we describe a Ni(II) N-confused porphyrin complex ( NiNCP ) featuring an acidic N-H group. It is readily deprotonated and exists in an anion form during catalysis. Owing to this functional site, NiNCP gave rise to an outstanding turnover number (TON) as high as 217,000 with a 98% selectivity for CO 2 reduction to CO, while the parent Ni(II) porphyrin ( NiTPP ) was found to be nearly inactive. Our mechanistic analysis revealed a nonclassical reaction pattern where CO 2 was effectively activated via the attack of the Lewis-basic ligand. The resulting ligand-bound CO 2 adduct could be further reduced to produce CO. This new metal-ligand synergistic effect is anticipated to inspire the design of highly active catalysts for small molecule activations.

Photoelectrochemical CO 2 reduction utilizing silicon-based photocathodes offers a promising route to directly store solar energy in chemical bonds, provoking the development of heterogeneous molecular catalysts with high turnover rates. Herein, an in situ surface transformation strategy is adopted to grow metal-organic frameworks (MOFs) on Si-based photocathodes, serving as catalytic scaffolds for boosting both the kinetics and selectivity of CO 2 reduction. Benefitting from the multi-junctional configuration for enhanced charge separation and the porous MOF scaffold enriching redox-active metalloporphyrin sites, the Si photocathode demonstrates a high CO faradaic efficiency of 87% at a photocurrent density of 10.2 mA cm -2 , which is among the best seen for heterogeneous molecular catalysts. This study highlights the exploitation of reticular chemistry and macrocycle complexes as Earth-abundant alternatives for catalyzing artificial photosynthesis.

The performance of lithium-metal batteries is severely hampered by uncontrollable dendrite growth and volume expansion on the metal anodes. Inspired by the "blockchain" concept in data mining, here we utilize a conductive polymer-filled metal-organic framework (MOF) as the lithium host, in which polypyrrole (PPy) serves as the "chain" to interlink Li "blocks" stored in the MOF pores. While the N-rich PPy guides fast Li + infiltration/extrusion and serves as the nucleation sites for isotropic Li growth, the MOF pores compartmentalize bulk Li deposition for 3D matrix Li storage, leading to low-barrier and dendrite-free Li plating/stripping with superb Coulombic efficiency. The as-fabricated lithium-metal anodes operate over 700 cycles at 5 mA cm -2 in symmetric cells, and 800 cycles at 1 C in full cells with a per-cycle capacity loss of only 0.017 %. This work might open a new chapter for Li-metal anode construction by introducing the concept of "blockchain" management of Li plating/stripping., (© 2022 Wiley-VCH GmbH.)

Water electrolysis for hydrogen production has long been regarded as an ideal tactic for renewable energy conversion and storage, but is impeded by the sluggish kinetics of both the hydrogen and oxygen evolution reactions, which are therefore in urgent need for high-performance but low-cost electrocatalysts. Herein, nanoframes of transition metal phosphides (TMPs) with the 3D framework carved open have been demonstrated as highly potent bifunctional catalysts for overall water splitting, reaching the benchmark performance of the Pt/C‖RuO 2 couple, and are much superior to their nanocubic counterparts. This excellent water splitting behavior can be attributed to the enlarged active surface area, less obstructed electrolyte infiltration, promoted charge transfer, and facilitated gas release. Further through in-depth activity analysis and post-electrocatalysis characterization, special attention has been paid to the fate and role of phosphorus in the electrocatalytic process, suggesting that despite the chemical instability of the TMPs (especially under OER conditions), excellent electrocatalytic stability can still be achieved through the amorphous bimetallic hydroxides/oxides formed in situ .

Inorganic defect halide compounds such as Cs 3 Bi 2 I 9 have been regarded as promising alternatives to overcome the instability and toxicity issues of conventional perovskite solar cells. However, their wide indirect bandgaps and deep defect states severely limit their photoelectronic conversion efficiency when implemented in devices. Trivalent cation substitution has been proposed by previous calculations allowing the engineering of their band structures, but experimental evidences are still lacking. Herein we use the trivalent cation Ru 3+ to partially replace Bi 3+ in Cs 3 Bi 2 I 9 , and reveal their structural and optoelectronic properties, as well as the environmental stability. The Ru-doped Cs 3 Bi 2 I 9 shows a decreasing bandgap with the increasing doping levels and an overall up-shift of band structure, owing to the dopant-induced defect states and thus enhanced phonon-electron coupling. As a result, upon Ru 3+ doping, the narrowed bandgap and the upward shift of the band structures might facilitate and broaden their applications in optoelectronic devices., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)