Materials Today Catalysis最新文献

Amorphous nanocatalysts have attracted significant attention due to their outstanding catalytic performance. Recent research has indicated that the performance of amorphous nanocatalysts is closely related to the short-to-medium-range order. This perspective aims to provide a comprehensive summary of the latest advances in understanding the significance of short-to-medium-range order in amorphous nanocatalysts and its correlation with catalytic performance. This perspective commences by presenting advanced methods employed for characterizing the short-to-medium-range order of amorphous nanocatalysts, including nanobeam electron diffraction, scanning transmission electron microscopy, atomic electron tomography, pair distribution function, and X-ray absorption fine structure spectroscopy. Next, the effect of short-to-medium-range order in determining the properties of amorphous nanocatalysts is discussed. Current challenges faced in amorphous nanocatalysts are eventually summarized with several prospective research directions. By identifying the obstacles and potential avenues for further exploration, this perspective aims to contribute valuable insights that will propel the development of high-efficient amorphous nanocatalysts.

The urgent demand for terawatt-scale clean energy necessitates the rational design of noble metal catalysts with minimal noble metal loading while maintaining high catalytic activity. However, the durability of low-loading catalysts is a critical concern for their successful industrial implementation. Here, we present a capping strategy using an amorphous HfO₂ (m-HfO₂) to address this issue. Take Pt/C catalysts with Pt loading as low as 81.39 ng cm⁻² as an example, we demonstrate that the m-HfO₂ layer (10 nm) serves as an efficient mass transport channel for underneath Pt active sites, and effectively mitigates bubble-induced blockage of active sites by separating bubble formation sites with Pt active sites. Thus, the resulting catalyst exhibits a remarkable mass activity of 122.87 A mg⁻¹ and an overpotential of 11 mV at 10 mA cm⁻². Furthermore, the m-HfO₂ plays a crucial role in eliminating the structural transformation and extending the lifetime of Pt-based catalysts, as evidenced by no loss of specific activity after consecutively cycling the catalyst for over 100 h. Such a capping strategy is potentially applied to other types of reactions and catalyst systems.

The synergistic catalysis of dual metal sites is vital for selective activation of complicated chemical bonds in biomass compounds. The base-free selective oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) using air as oxidant and water as solvent is a highly sustainable upgrading process for cellulosic carbohydrates. In this work, a series of Pt_xRu-MgAlO (x = 0.5, 1, 2 and 3, in mole) nanocatalysts with controlled particle sizes (ca. 2 nm) were synthesized by a PVP-assisted adsorption method. The Pt₂Ru-MgAlO catalyst showed 99% selectivity of FDCA with full conversion of HMF at only 100 °C under 0.2 MPa of air. In the meantime, an initial reaction rate of HMF of 2.8 mmol mol_M⁻¹ s⁻¹ and an intrinsic turnover frequency of 61.5 h⁻¹ were attained, respectively. Besides, this catalyst exhibited superior stability during five consecutive reuses without metal leaching. It was disclosed that the Pt-Ru interaction played critical roles in determining the intrinsic activity and the CO bond activation of the prepared Pt_xRu-MgAlO catalysts. Kinetic experiments combined with in situ chemisorption techniques clearly unraveled adsorption and activation processes of CO bond on Pt⁰-Ru⁰ sites. To the best of our knowledge, this work firstly reported a PtRu bimetallic catalyst for aerobic oxidation of HMF and provided insight into synergistic catalysis.

To improve the utilization efficiency of noble metals as well as lower their mass loading in electrocatalysis, the research community has contributed significant efforts to nanostructure noble metal catalysts in various dimensions during recent decades, such as porous structures (3D), nanosheets (2D), nanowires (1D), nanoclusters (0D), and individual atoms (i.e., single-atom catalyst). Recently, with the development of the well-controlled synthesis of atom-thin materials (e.g., the noble metal layer or two-dimensional materials), a new type of catalyst defined as the single-atom-layer catalyst, has emerged, allowing nearly all the atoms at the monolayer to be accessible to catalytic reactions. In this perspective, we first introduced the unique properties of this catalyst and distinguished it from current single-atom catalysts, then highlighted its recent theoretical and experimental progress, and finally discussed critical challenges toward catalytic applications.

Due to the unique structure and electronic properties of low-dimensional materials, enormous potential can be achieved over low-dimensional materials for high-efficiency photocatalytic activity. Metal sulfide semiconductors with abundant optionality of various metal element, multi metal combination and ratio regulation shows favorable electronic structure adjustability. This review summarizes recent advances in the design, tuning and photocatalytic applications of low-dimensional metal sulfides. We start with the introduction of multifarious types of low-dimensional metal sulfides photocatalysts, including binary metal sulfides (such as CdS, ZnS, MoS₂, SnS, SnS₂, Bi₂S₃, In₂S₃, CuS, ReS₂), ternary metal sulfides (such as In₄SnS₈, ZnIn₂S₄, CdIn₂S₄, CuInS₂, CuIn₅S₈) and others (such as Cu-Zn-In-S, Cu-Zn-Ga-S, CuInP₂S₆, AgInP₂S₆). Then, the tuning strategies to improve the photocatalytic performance of low-dimensional metal sulfides have been summarized with the emphasis on structure–performance correlation, such as facet engineering, exposure of active edges, elemental doping, defect engineering, co-catalyst loading, single atom engineering, polarization enhancement and junction construction. The advancements in versatile photocatalytic applications of low-dimensional metal sulfides–based photocatalysts in the areas of environmental purification, water splitting, CO₂ reduction, N₂ reduction and organic synthesis are discussed. Finally, we end this review with a look into the opportunities and challenges of low-dimensional metal sulfides in future study.

Water electrolysis is a green technology for hydrogen fuel production, but greatly hampered by the slow kinetics of the anodic oxygen evolution reaction (OER) and the cathodic hydrogen evolution reaction (HER). In this work, we report an efficient strategy to simultaneously promote OER and HER performance on Co₃O₄ hexagonal nanosheets via Fe-doping-induced cation substitution and anion vacancies. Benefiting from the integrated advantages of well-defined ultrathin nanosheets, abundant vacancies, and unique three-dimensional electrode configuration, the optimized Fe-doped Co₃O₄ hexagonal nanosheets/nickel foam (Fe_0.4Co_2.6O₄ HNSs/NF) can achieve overpotentials of 328 mV at 100 mA cm⁻² for OER and 315 mV at 500 mA cm⁻² for HER, respectively, which is comparable to those of the benchmark noble electrocatalysts. More importantly, the Fe_0.4Co_2.6O₄ HNSs/NF-assembled electrolyzer for overall water splitting can deliver a current density of 100 mA cm⁻² at a cell voltage as low as 1.66 V and work steadily at 50 mA cm⁻² with a negligible fading up to 140 h.

Layered graphitic carbon nitride (g-C₃N₄) has sparked extensive interest in energy applications due to the unique physicochemical properties, tunable molecular structure, and high stability. Herein, we review the research progress of g-C₃N₄-based electrocatalysts for energy applications and summarize their design strategies from the perspectives of surface engineering and interfacial engineering, including heteroatom doping, defect engineering, and heterostructure engineering. Finally, we provide perspectives on the challenges and future directions of g-C₃N₄-based electrocatalysts. This review would inspire new ideas into the development of next-generation g-C₃N₄-based electrocatalysts with improved performance toward the sustainable and clean energy conversion systems.