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Pt single-atom materials possess an ideal atom economy but suffer from limited intrinsic activity and side reaction of producing H2O2in catalyzing the oxygen reduction reaction (ORR); platinum alloys have higher intrinsic activity but weak stability. Here, we demonstrate that anchoring platinum alloys on single-atom Pt-decorated carbon (Pt-SAC) surmounts their inherent deficiencies, thereby enabling a complete four-electron ORR pathway catalysis with high efficiency and durability. Pt3Co@Pt-SAC demonstrates an exceptional mass and specific activities 1 order of magnitude higher than those of commercial Pt/C. They are durable throughout 50000 cycles, showing only a 10 mV decay in half-wave potential. An in situRaman analysis and theoretical calculations reveal that Pt3Co core nanocrystals modulate electron structures of the adjacent Pt single atoms to facilitate the intermediate absorption for fast kinetics. The superior durability is attributed to the shielding effect of the Pt-SAC coating, which significantly mitigates the dissolution of Pt3Co cores. The hybridizing strategy might promote the development of highly active and durable ORR catalysts.

In this work, CeO2quantum dots were anchored on the surface of oxygen defected CdWO4nanorods through a simple precipitation procedure to construct an efficient S-scheme heterojunction. The as-fabricated pristine and hybrid photocatalysts were thoroughly characterized by XRD, BET, SEM, HRTEM, and XPS analyses and applied for the photoreduction of CO2and photocatalytic hydrogen evolution under simulated sunlight irradiation. The results revealed that CH4and CO were the major products and CH3OH was detected as the side product from the photoreduction of CO2. The photoreduction yield of the heterojunction was substantially improved with the addition of CeO2as compared to the pure samples, and the heterojunction containing 40 mol % CeO2showed the highest efficiency. This improvement could be mainly ascribed to the higher reduction potential of the separated electrons and exceptional mobility of charge carriers. Additionally, the adsorption of CO2and hydroxyl groups was increased due to the increased density of oxygen vacancy sites at the interfacial contacts acting as trapping centers for photoexcited electrons. Based on the experimental and theoretical results, S-scheme charge transfer was proposed for the fabricated CdWO4-CeO2heterojunction.

Upgrading of biomass wastes to value-added materials has been incessantly pursued worldwide with diverse applications, especially deploying photocatalytic composites encompassing metal oxides with acidic and carbon compounds. Herein, the fabrication of a morphologically unique acidic catalyst encompassing a two-dimensional (2D) TiO2/g-C3N4heterojunction feature is described for the generation of 5-hydroxymethylfurfural (5-HMF), which exploits the acidic/ionic liquid (IL) bifunctional photocatalysis under visible light. The structural integrity of the synthesized TiO2/g-C3N4/SO3H(IL) was corroborated by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy–energy-dispersive spectroscopy (EDX–EDS), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), UV–vis, Tauc plots, transmission electron microscopy (TEM), and Brunauer–Emmett–Teller–Barrett–Joyner–Halenda (BET–BJH) analyses. Keeping environmental impact in mind, there are compelling advantages in the development of bio-derived pathways to access ILs from natural renewable resources. The outcomes of environmental assessments have revealed that the incorporation of TiO2in g-C3N4and ClSO3H can reduce the probability of recombination due to ionic charges present, therefore enhancing the photocatalytic activity via the transformation of cellulose and glucose to produce 5-HMF in higher yields, with the optimum conditions being reaction in water under a blue light-emitting diode (LED), at 100 °C, for 1–1.5 h. The main advantages of this production method include minimum number of synthetic steps as well as ample availability of and easy access to primary ingredients. While a significant volume of 5-HMF was produced under blue light-emitting diode (LED) radiation, the selectivity was drastically reduced in the dark. The salient attributes of the catalyst comprise stability in air, robustness, reusability, and its overall superior activity that is devoid of hazardous additives or agents. This inimitable method has uncovered a newer strategy for enhancing the photocatalytic attributes of deployed semiconducting materials for numerous photocatalytic functions while adhering to the tenets of environmental friendliness.