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Targeted synthesis of acetic acid (CH3COOH) from CO2 photoreduction under mild conditions mainly limits by the kinetic challenge of the C−C coupling. Herein, we utilized doping engineering to build charge‐asymmetrical metal pair sites for boosted C−C coupling, enhancing the activity and selectivity of CO2 photoreduction towards CH3COOH. As a prototype, the Pd doped Co3O4 atomic layers are synthesized, where the established charge‐asymmetrical cobalt pair sites are verified by X‐ray photoelectron spectroscopy and X‐ray absorption near edge spectroscopy spectra. Theoretical calculations not only reveal the charge‐asymmetrical cobalt pair sites caused by Pd atom doping, but also manifest the promoted C−C coupling of double *COOH intermediates through shortening of the coupled C−C bond distance from 1.54 to 1.52 Å and lowering their formation energy barrier from 0.77 to 0.33 eV. Importantly, the decreased reaction energy barrier from the protonation of two*COOH into *CO intermediates for the Pd‐Co3O4 atomic layer slab is 0.49 eV, higher than that of the Co3O4 atomic layer slab (0.41 eV). Therefore, the Pd‐Co3O4 atomic layers exhibit the CH3COOH evolution rate of ca. 13.8 μmol g−1 h−1 with near 100% selectivity, both of which outperform all previously reported single photocatalysts for CO2 photoreduction towards CH3COOH under similar conditions. [ABSTRACT FROM AUTHOR]

The development of reticular chemistry has enabled the construction of a large array of metal–organic frameworks (MOFs) with diverse net topologies and functions. However, dominating this class of materials are those built from discrete/finite secondary building units (SBUs), yet the designed synthesis of frameworks involving infinite rod‐shaped SBUs remain underdeveloped. Here, by virtue of a global linker desymmetrization approach, we successfully targeted a novel Cu‐MOF (Cu‐ASY) incorporating infinite Cu‐carboxylate rod SBUs with its structure determined by micro electron diffraction (MicroED) crystallography. Interestingly, the rod SBU can be simplified as a unique cylindric sphere packing qbe tubule made of [43.62] tiles, which further connect the tritopic linkers to give a newly discovered 3,5‐connected gfc net. Cu‐ASY is a permanent ultramicroporous material featuring 1D channels with highly inert surfaces and shows a preferential adsorption of propane (C3H8) over propene (C3H6). The efficiency of C3H8 selective Cu‐ASY is validated by multicycle breakthrough experiments, giving C3H6 productivity of 2.2 L/kg. Density functional theory (DFT) calculations reveal that C3H8 molecules form multiple C−H⋅⋅⋅π and atypical C−H⋅⋅⋅ H−C van der Waals interactions with the inner nonpolar surfaces. This work therefore highlights the linker desymmetrization as an encouraging and intriguing strategy for achieving unique MOF structures and properties. [ABSTRACT FROM AUTHOR]

Electrocatalytic nitrogen oxidation reaction (NOR) offers an efficient and sustainable approach for conversion of widespread nitrogen (N2) into high‐value‐added nitrate (NO3−) under mild conditions, representing a promising alternative to the traditional approach that involves harsh Haber–Bosch and Ostwald oxidation processes. Unfortunately, due to the weak absorption/activation of N2 and the competitive oxygen evolution reaction, the kinetics of NOR process is extremely sluggish accompanied with low Faradaic efficiencies and NO3− yield rates. In this work, an oxygen‐vacancy‐enriched perovskite oxide with nonstoichiometric ratio of strontium and ruthenium (denoted as Sr0.9RuO3) was synthesized and explored as NOR electrocatalyst, which can exhibit a high Faradaic efficiency (38.6 %) with a high NO3− yield rate (17.9 μmol mg−1 h−1). The experimental results show that the amount of oxygen vacancies in Sr0.9RuO3 is greatly higher than that of SrRuO3, following the same trend as their NOR performance. Theoretical simulations unravel that the presence of oxygen vacancies in the Sr0.9RuO3 can render a decreased thermodynamic barrier toward the oxidation of *N2 to *N2OH at the rate‐determining step, leading to its enhanced NOR performance. [ABSTRACT FROM AUTHOR]

Photocatalytic CO2 reduction (PCR) expresses great attraction to convert useless greenhouse gas into valuable chemical feedstock. However, the weak interactions between catalytic sites and PCR intermediates constrains the PCR activity and selectivity. Herein, we proposed a new strategy to match the intermediates due to the maximum orbital overlap of catalytic sites and C1 intermediates by establishing dual Jahn–Teller (J–T) sites, in which, the strongly asymmetric J–T sites can break the nonpolar CO2 molecules and self‐adapt the different structure of C1 intermediates. Taking cobalt carbonate hydroxide as an example, the weakly symmetric dual cobalt (Co2) dual J–T sites, weakly asymmetric Fe&Co sites and strongly asymmetric Cu&Co sites were assembled. After illumination, the interaction between dual J–T sites and the CO2 molecules enhances J–T distortion, which further modulates the PCR activity and selectivity. As a result, the Cu&Co sites exhibited CO yield of 8137.9 μmol g−1, about 2.3‐fold and 4.2‐fold higher than that of the Fe&Co and Co2 sites within 5‐hour photoreaction, respectively. In addition, the selectivity achieved as high as 92.62 % than Fe&Co (88.67 %) and Co2 sites (55.33 %). This work provides a novel design concept for the construction of dual J–T sites to regulate the catalytic activity and selectivity. [ABSTRACT FROM AUTHOR]

Developing adsorptive separation processes based on C2H6‐selective sorbents to replace energy‐intensive cryogenic distillation is a promising alternative for C2H4 purification from C2H4/C2H6 mixtures, which however remains challenging. During our studies on two isostructural metal–organic frameworks (Ni‐MOF 1 and Ni‐MOF 2), we found that Ni‐MOF 2 exhibited significantly higher performance for C2H6/C2H4 separation than Ni‐MOF‐1, as clearly established by gas sorption isotherms and breakthrough experiments. Density‐Functional Theory (DFT) studies showed that the unblocked unique aromatic pore surfaces within Ni‐MOF 2 induce more and stronger C−H⋅⋅⋅π with C2H6 over C2H4 while the suitable pore spaces enforce its high C2H6 uptake capacity, featuring Ni‐MOF 2 as one of the best porous materials for this very important gas separation. It generates 12 L kg−1 of polymer‐grade C2H4 product from equimolar C2H6/C2H4 mixtures at ambient conditions. [ABSTRACT FROM AUTHOR]

Selective CO2 photoreduction into C2 fuels under mild conditions suffers from low product yield and poor selectivity owing to the kinetic challenge of C−C coupling. Here, triatomic sites are introduced into bimetallic sulfide to promote C−C coupling for selectively forming C2 products. As an example, FeCoS2 atomic layers with different oxidation degrees are first synthesized, demonstrated by X‐ray photoelectron spectroscopy and X‐ray absorption near edge spectroscopy spectra. Both experiment and theoretical calculation verify more charges aggregate around the introduced oxygen atom, which enables the original Co−Fe dual sites to turn into Co−O−Fe triatomic sites, thus promoting C−C coupling of double *COOH intermediates. Accordingly, the mildly oxidized FeCoS2 atomic layers exhibit C2H4 formation rate of 20.1 μmol g−1 h−1, with the product selectivity and electron selectivity of 82.9 % and 96.7 %, outperforming most previously reported photocatalysts under similar conditions. [ABSTRACT FROM AUTHOR]

To understand the role of structure imperfections on the performance of electrochromic transition metal oxide (ETMO) is challenging for the design of efficient smart windows. Herein, we investigate the performance evolution with tunable crystallographic imperfections for rutile TiO2 nanowire film (TNF). Structure imperfections, originating mainly from the copious oxygen deficiency, are apt to cumulatively retard the shuttling ions, resulting in the response rate for raw TNF being less than the half that of TNF annealed at 500 °C. We describe ion accommodation sites as a convolution of normal site and abnormal site, in which the normal site performs reversible coloration but the abnormal site contributes only to charge storage, which gives a rationale for the non‐linear coloration and rate capability loss. These findings give a clear picture of the ion shuttling process, which is insightful for enhancing the electrochromic performance via structure reprogramming. [ABSTRACT FROM AUTHOR]

Herein, we first design a model of reversible redox‐switching metal–organic framework single‐unit‐cell sheets, where the abundant metal single sites benefit for highly selective CO2 reduction, while the reversible redox‐switching metal sites can effectively activate CO2 molecules. Taking the synthetic Cu‐MOF single‐unit‐cell sheets as an example, synchrotron‐radiation quasi in situ X‐ray photoelectron spectra unravel the reversible switching CuII/CuI single sites initially accept photoexcited electrons and then donate them to CO2 molecules, which favors the rate‐liming activation into CO2δ−, verified by in situ FTIR spectra and Gibbs free energy calculations. As an outcome, Cu‐MOF single‐unit‐cell sheets achieve near 100 % selectivity for CO2 photoreduction to CO with a high rate of 860 μmol g−1 h−1 without any sacrifice reagent or photosensitizer, where both the activity and selectivity outperform previously reported photocatalysts evaluated under similar conditions. [ABSTRACT FROM AUTHOR]

The chemical conversion of CO2 to long‐chain chemicals is considered as a highly attractive method to produce value‐added organics, while the underlying reaction mechanism remains unclear. By constructing surface vacancy‐cluster‐mediated solid frustrated Lewis pairs (FLPs), the 100 % atom‐economical, efficient chemical conversion of CO2 to dimethyl carbonate (DMC) was realized. By taking CeO2 as a model system, we illustrate that FLP sites can efficiently accelerate the coupling and conversion of key intermediates. As demonstrated, CeO2 with rich FLP sites shows improved reaction activity and achieves a high yield of DMC up to 15.3 mmol g−1. In addition, by means of synchrotron radiation in situ diffuse reflectance infrared Fourier‐transform spectroscopy, combined with density functional theory calculations, the reaction mechanism on the FLP site was investigated systematically and in‐depth, providing pioneering insights into the underlying pathway for CO2 chemical conversion to long‐chain chemicals. [ABSTRACT FROM AUTHOR]

Here, noble‐metal‐doped two‐dimensional metal oxide nanosheets are designed to realize selective CO2 photoreduction to CH4. As a prototype, Pd‐doped CeO2 nanosheets are fabricated, where the active sites of Pdδ+ (2<δ<4) and Ce3+−Ov are revealed by quasi in situ X‐ray photoelectron spectra and in situ electron paramagnetic resonance spectra. Moreover, in situ Fourier‐transform infrared spectra of D2O photodissociation and desorption verify the existence of the Pd−OD bond, implying that Pdδ+ sites can participate in water oxidation to deliver H* species for facilitating the protonation of the intermediates. Furthermore, theoretical calculations suggest the Pd doping could regulate the formation energy barrier of the key intermediates CO* and CH3O*, thus making CO2 reduction to CH4 become the favorable process. Accordingly, Pd‐doped CeO2 nanosheets achieve nearly 100 % CH4 selectivity of CO2 photoreduction, with the raising CH4 evolution rate of 41.6 μmol g−1 h−1. [ABSTRACT FROM AUTHOR]

Chemical fixation of carbon dioxide (CO2) into value‐added organics is regarded as a competitive and viable method in large scale industrial production, during which the catalysts with promoting CO2 activation ability are needed. Herein, we proposed an in‐plane heterostructure strategy to construct Lewis acid–base sites for efficient CO2 activation. By taking ultrathin in‐plane Cu2O/Cu heterostructures as a prototype, we show that Lewis acid‐base sites on heterointerface can facilitate a mixed C and O dual coordination on surface, which not only strengthen CO2 adsorption, but also effectively activate the inert molecules. As revealed by in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and quasi in situ X‐ray photoelectron spectroscopy (XPS), Lewis acid‐base sites could readily activate CO2 to.CO2− species, which is the key intermediate radical for CO2 fixation. As a result, abundant Lewis acid–base sites endow Cu2O/Cu nanosheets with excellent performances for dimethyl carbonate generation, a high conversion yield of 28 % with nearly 100 % selectivity under mild conditions. This study provides a model structure for CO2 fixation reactions. [ABSTRACT FROM AUTHOR]

Clean hydrogen evolution through electrochemical water splitting underpins various innovative approaches to the pursuit of sustainable energy conversion technologies, but it is blocked by the sluggish anodic oxygen evolution reaction (OER). The hydrazine oxidation reaction (HzOR) has been considered as one of the most promising substitute for OER to improve the efficiency of hydrogen evolution reaction (HER). Herein, we construct novel dual nanoislands on Ni/C hybrid nanosheet array: one kind of island represents the part of bare Ni particle surface, while the other stands for the part of core–shell Ni@C structure (denoted as Ni‐C HNSA), in which exposed Ni atoms and Ni‐decorated carbon shell perform as active sites for HzOR and HER respectively. As a result, when the current density reaches 10 mA cm−2, the working potentials are merely −37 mV for HER and ‐20 mV for HzOR. A two‐electrode electrolyzer exhibits superb activity that only requires an ultrasmall cell voltage of 0.14 V to achieve 50 mA cm−2. [ABSTRACT FROM AUTHOR]

Herein, we first design a fast low‐pressure ultraviolet light irradiation strategy for easily regenerating the nearly equivalent surface vacancies. Taking the defective Bi2O2CO3 nanosheets as an example, nearly equal amount of oxygen vacancies can be regenerated under UV light irradiation. Synchrotron‐radiation quasi in situ X‐ray photoelectron spectra disclose the Bi sites in the O‐defective Bi2O2CO3 nanosheets can act as the highly active sites, which not only help to activate CO2 molecules, but also contribute to stabilizing the rate‐limiting COOH* intermediate. Also, in situ Fourier transform infrared spectroscopy and in situ mass spectrometry unravel the UV light irradiation contributes to accelerating CO desorption process. As a result, the O‐defective Bi2O2CO3 nanosheets achieve a stability up to 2640 h over 110 cycling tests and a high evolution rate of 275 μmol g−1 h−1 for visible‐light‐driven CO2 reduction to CO. [ABSTRACT FROM AUTHOR]

Reported here is the first highly selective conversion of various waste plastics into C2 fuels under simulated natural environment conditions by a sequential photoinduced C−C cleavage and coupling pathway, where single‐use bags, disposable food containers, food wrap films, and their main components of polyethylene, polypropylene, and polyvinyl chloride can be photocatalytically transformed into CH3COOH without using sacrificial agents. As an example, polyethylene is photodegraded 100 % into CO2 within 40 h by single‐unit‐cell thick Nb2O5 layers, while the produced CO2 is further photoreduced to CH3COOH. Various methods and experiments disclose that O2 and.OH radicals trigger the oxidative C−C cleavage of polyethylene to form CO2, while other investigations show that the yielded CH3COOH stems from CO2 photoreduction by C−C coupling of.COOH intermediates. This two‐step plastic‐to‐fuel conversion may help to simultaneously address the white pollution crisis and harvest highly valuable multicarbon fuels in natural environments. [ABSTRACT FROM AUTHOR]

Nitrate is a raw ingredient for the production of fertilizer, gunpowder, and explosives. Developing an alternative approach to activate the N≡N bond of naturally abundant nitrogen to form nitrate under ambient conditions will be of importance. Herein, pothole‐rich WO3 was used to catalyse the activation of N≡N covalent triple bonds for the direct nitrate synthesis at room temperature. The pothole‐rich structure endues the WO3 nanosheet more dangling bonds and more easily excited high momentum electrons, which overcome the two major bottlenecks in N≡N bond activation, that is, poor binding of N2 to catalytic materials and the high energy involved in this reaction. The average rate of nitrate production is as high as 1.92 mg g−1 h−1 under ambient conditions, without any sacrificial agent or precious‐metal co‐catalysts. More generally, the concepts will initiate a new pathway for triggering inert catalytic reactions. Hole in one: The use of pothole‐rich WO3 as a catalyst enables the activation of N≡N covalent triple bonds for direct nitrate synthesis at room temperature. The average nitrate‐producing rate is as high as 1.92 mg g−1 h−1 under ambient conditions, without any sacrificial agent or precious‐metal co‐catalysts. [ABSTRACT FROM AUTHOR]