In Fenton or Fenton-like reactions, ·OH obtained by the reductive activation of H2O2 is regarded as the major reactive oxygen species (ROS); however, the generation of other ROS like O2·– and 1O2 cannot be negligible. Since the degradation capability of a certain ROS would be varied to distinctive pollutants, the regulation of ROS production from H2O2 activation should be applicable for a more targeted pollutant degradation. Herein, a series of carbon nitride (C3N4)-supported Fe catalysts with the state of Fe ranging among single-atom, oxide-cluster, and nanoparticle catalysts were fabricated and their activities in photo-Fenton reactions were evaluated. It was uncovered that the single-atom catalyst favored the generation of O2·– and 1O2 via the oxidative activation of H2O2 and the selectivity of 1O2 toward ·OH dynamically increased with the proceeding of H2O2 activation, while the catalysts with an abundance of oxide clusters exhibited a significantly higher conversion of H2O2 to ·OH. In situ FT-IR studies demonstrated that during the H2O2 activation, the single-atom catalyst underwent a more significant surface hydroxylation than the oxide-cluster catalyst. Such a result was further consolidated by the theoretical calculation that the adsorption energy of surface hydroxyl was remarkably higher on the single-atom catalyst. Thereafter, distinctive from the easy desorption of hydroxyl during the reduction of H2O2 to ·OH in oxide-cluster catalysts, the in situ surface hydroxylation on the single-atom catalyst alters the adsorption mode of H2O2 to a H-bonded structure, which steers the selectivity of ROS generation to a more favored oxidative transformation of H2O2 to O2·–/1O2. This work uncovers the decisive role of surface hydroxyl in regulating ROS generation in a heterogeneous Fenton reaction.
Abstract Herein, we fabricated a π–π stacking hybrid photocatalyst by combining two two‐dimensional (2D) materials: g‐C 3 N 4 and a Cu‐porphyrin metal–organic framework (MOF). After an aerobic photocatalytic pretreatment, this hybrid catalyst exhibited an unprecedented ability to photocatalytically reduce CO 2 to CO and CH 4 under the typical level (20 %) of O 2 in the air. Intriguingly, the presence of O 2 did not suppress CO 2 reduction; instead, a fivefold increase compared with that in the absence of O 2 was observed. Structural analysis indicated that during aerobic pretreatment, the Cu node in the 2D‐MOF moiety was hydroxylated by the hydroxyl generated from the reduction of O 2 . Then the formed hydroxylated Cu node maintained its structure during aerobic CO 2 reduction, whereas it underwent structural alteration and was reductively devitalized in the absence of O 2 . Theoretical calculations further demonstrated that CO 2 reduction, instead of O 2 reduction, occurred preferentially on the hydroxylated Cu node.
Regulating the spintronic structure of electrocatalysts can improve the oxygen evolution reaction performance efficiently. Nonetheless, the effects of tuning the spintronic structure for the oxygen evolution reaction mechanisms have rarely been discussed. Here, we show a ruthenium-cobalt-tin oxide with optimized spintronic structure due to the quantum spin interaction of Ru and Co. The specific spintronic structure of ruthenium-cobalt-tin oxide promotes the charge transfer kinetics and intermediates evolution behavior under applied potential, generating long-lived active species with higher spin density sites for the oxygen evolution reaction after the reconstruction process. Moreover, the ruthenium-cobalt-tin oxide possesses decoupled proton-electron transfer procedure during the oxygen evolution reaction process, demonstrating that the electron transfer procedure of O-O bond formation between *O intermediate and lattice oxygen in Co-O-Ru is the rate-determining step of the oxygen evolution reaction process. This work provides rational perspectives on the correlation between spintronic structure and oxygen evolution reaction mechanism. Tuning the spintronic structure in oxygen evolution reactions is underexplored, despite its potential to enhance catalytic performance. Here, the authors report a ruthenium-cobalt-tin oxide with an optimized spintronic structure, highlighting its improved performance and reaction mechanisms.
Abstract Photocatalytic conversion of CO 2 and H 2 O into fuels and oxygen is a highly promising solution for carbon‐neutral recycling. Traditionally, researchers have studied CO 2 reduction and H 2 O oxidation separately, overlooking potential synergistic interplay between these processes. This study introduces an innovative approach, spatial synergy, which encourages synergistic progress by bringing the two half‐reactions into atomic proximity. To facilitate this, we developed a defective ZnIn 2 S 4 ‐supported single‐atom Cu catalyst (Cu−SA/D−ZIS), which demonstrates remarkable catalytic performance with CO 2 reduction rates of 112.5 μmol g −1 h −1 and water oxidation rates of 52.3 μmol g −1 h −1 , exhibiting a six‐fold enhancement over D−ZIS. The structural characterization results indicated that the trapping effect of vacancy associates on single‐atom copper led to the formation of an unsaturated coordination structure, Cu‐S 3 , consequently giving rise to the Cu Zn ′ V S ⋅⋅ V Zn “ defect complexes. FT‐IR studies coupled with theoretical calculations reveal the spatially synergistic CO 2 reduction and water oxidation on Cu Zn ′ V S ⋅⋅ V Zn ”, where the breakage of O−H in water oxidation is synchronized with the formation of *COOH, significantly lowering the energy barrier. Notably, this study introduces and, for the first time, substantiates the spatial synergy effect in CO 2 reduction and H 2 O oxidation through a combination of experimental and theoretical analyses, providing a fresh insight in optimizing photocatalytic system.
Plasmonic photocatalysts have been emerging as a promising candidate for solar energy conversion and environmental remediation. However, those metallic plasmonic photocatalysts inevitably suffer from surface reconstruction and corrosion under harsh reaction conditions, leading to a low activity and poor chemical photostability. Herein, we observe a simultaneous improvement of both activity and photostability on Au/TiO2 nanostructure-based photoanodes induced by an in situ plasmon-mediated electrochemical activation (PMEA) treatment under photoelectrochemical (PEC) water oxidation conditions. Detailed PEC studies demonstrate that the PMEA treatment generates electron-rich surface states at Au/TiO2 interfaces, which results in a high interface charge-transfer efficiency of above 80% and boosts water oxidation activity by 100%. The electron-rich surface states further enhance the PEC stability by reducing the excessive charge accumulation at interfaces and preventing the dissolution of Au. The photoanodes are further tested for the degradation of an antibiotic, ciprofloxacin, which exhibited high PEC activity and stability. Our work provides a convenient method for improving the efficiency and chemical photostability of plasmonic photocatalysts.
Selective photooxidation reactions offer a promising route for transformation of organic pollutants into high-value products under mild conditions. In this work, we demonstrate that the edge functional groups in polymer carbon nitride (PCN) were key to the selectivity of methyl mercaptan (CH3SH) photocatalytic oxidation. The amino-decorated PCN favors the oxidation of the -SH group of CH3SH to forming CH3SO3H with selectivity up to 84.0%, while cyanamide-enriched PCN prefers to breaking the -CH3 end of CH3SH and produce H2SO4 with selectivity of 82.0%. The totally difference in reaction sites is ascribed to the functional-group-modulated electronic structure of PCN, which determines activity of photoinduced carriers and the molecular oxygen activation pathway. The amino- and cyanamide-decorated PCN leads to preferential generation of 1O2 and ·O2-, respectively. This study highlights the significant role of edge groups engineering in modulation of the excitonic effects in PCN and the resultant selectivity control during photocatalytic reaction.
Abstract Epoxides are significant intermediates for the manufacture of pharmaceuticals and epoxy resins. In this study, we develop a Br − /BrO − mediated photoelectrochemical epoxidation system on α-Fe 2 O 3 . High selectivity (up to >99%) and faradaic efficiency (up to 82 ± 4%) for the epoxidation of a wide range of alkenes are achieved, with water as oxygen source, which are far beyond the most reported electrochemical and photoelectrochemical epoxidation performances. Further, we can verify that the epoxidation reaction is mediated by Br − /BrO − route, in which Br − is oxidized non-radically to BrO − by an oxygen atom transfer pathway on α-Fe 2 O 3 , and the formed BrO − in turn transfers its oxygen atom to the alkenes. The non-radical mediated characteristic and the favorable thermodynamics of the oxygen atom transfer process make the epoxidation reactions very efficient. We believe that this photoelectrochemical Br − /BrO − -mediated epoxidation provides a promising strategy for value-added production of epoxides and hydrogen.
Bismuth vanadate ranks among the most promising photoanodes for photoelectrochemical water splitting. Nonetheless, slow charge separation and transport are key barriers to its photoefficiency. Here, we present a co‐doping strategy that significantly improves the charge separation performance of BVO. Under standard one sun illumination, the Fe‐N co‐doped BVO photoanode (Fe‐N‐BVO) by N‐coordinated Fe precursor reaches a record photocurrent density of 7.01 mA cm‐2 at 1.23 V vs RHE after modified a surface co‐catalyst. By contrast, much lower photocurrent density is obtained for the N‐doped and Fe‐doped BVO with separated N and Fe precursors. The detailed characterizations show that the high activity of the Fe‐N‐BVO is attributed to the enhanced photo‐induced bulk charge separation and the accelerated surface water oxidation kinetics. XPS, EXAFS and DFT calculations clearly show that, instead of formation of deep trapping state in the individually doped BVO, the co‐doping of Fe‐N into BVO generates Fe‐based electronic states just below the bottom of conduction band and N‐derived states just above the top of valence band. Such modulations in electronic structure enable the efficient trap of the electrons and holes to enhance the separation of photo‐induced carriers, but hinder the charge recombination originated from the deep trapping sites.
There is a widespread perception that Chinese companies, compared to their Western counterparts, are not good at creating novel products and services. But in the arenas of e-commerce and other digital businesses, Chinese companies such as Alibaba and Tencent have become highly successful. This has led some observers to hypothesize that while Chinese firms may not excel at developing new-to-the-world products and services, they may be very good in inventing new-to-the- world business models (BMs). To explore this phenomenon, we analyzed 137 suggested innovative BMs in detail to investigate new-to-the- world features, yielding an overview of business model innovation (BMI) in China. Based on these cases, we propose a theoretical framework to show how innovative features can prompt successful BMI. We summarize the lessons to be learned from BMI in China.
Herein, we fabricated a π-π stacking hybrid photocatalyst by combining two two-dimensional (2D) materials: g-C3 N4 and a Cu-porphyrin metal-organic framework (MOF). After an aerobic photocatalytic pretreatment, this hybrid catalyst exhibited an unprecedented ability to photocatalytically reduce CO2 to CO and CH4 under the typical level (20 %) of O2 in the air. Intriguingly, the presence of O2 did not suppress CO2 reduction; instead, a fivefold increase compared with that in the absence of O2 was observed. Structural analysis indicated that during aerobic pretreatment, the Cu node in the 2D-MOF moiety was hydroxylated by the hydroxyl generated from the reduction of O2 . Then the formed hydroxylated Cu node maintained its structure during aerobic CO2 reduction, whereas it underwent structural alteration and was reductively devitalized in the absence of O2 . Theoretical calculations further demonstrated that CO2 reduction, instead of O2 reduction, occurred preferentially on the hydroxylated Cu node.
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