Regulating Phase Junction and Oxygen Vacancies of TiO2 Nanoarrays for Boosted Photoelectrochemical Water Oxidation

Sight into a Rare-Earth-Based Catalyst with Spatial Confinement Effect from the Perspective of Electronic Structure

Rare-earth elements include 15 kinds of lanthanides as well as Sc and Y elements. Interestingly, the special electronic configuration of a lanthanide rare earth is [Xe]4fn5d0-16s2 (n = 0-14), which results in rare-earth materials' unique activity in such areas as thermal catalysis, electrocatalysis, photocatalysis, etc. It is worth noting that a class of materials with spatial confinement effects are playing an increasingly important role in the catalytic performance; especially, the construction of hollow multishelled structures (HoMSs) can further enhance the activity of rare-earth catalytic materials. In this review, we discuss in depth the important roles of the rare-earth 4f5d electronic structure. Subsequently, this review systematically summarizes the synthesis methods of rare-earth HoMSs and their research progress in the field of catalysis and specifically introduces the advanced characterization and analysis methods of rare-earth HoMSs. Finally, the research directions, application prospects, and challenges that need to be focused on in the future of rare-earth-based HoMSs are discussed and anticipated. We believe that this review will not only inspire more creativity in optimizing the local electronic structure and spatial confinement structure design of rare-earth-based catalysts but also provide valuable insights for designing other types of catalysts.

Multivariate analysis on the structure-activity parameters for nano CuOx-catalyzed reduction reactions

Understanding the origin of enhanced catalytic activity is critical to heterogeneous catalyst design. This is especially important for non-noble metal-based catalysts, notably metal oxides, which have recently emerged as viable alternatives for numerous thermal catalytic processes. For thermal catalytic reduction/hydrogenation using metal oxide nanoparticles, enhanced catalytic performance is typically attributed to increased surface area and oxygen vacancies. Concomitantly, the treatments that induce oxygen vacancies also impact other material parameters such as microstrain, crystallinity, oxidation state, and particle shape. Herein, multivariate statistical analysis is used to disentangle the impact of material properties of CuO nanoparticles on catalytic rates for nitroaromatic reduction and methylene blue reduction. The impact of microstrain, shape, and Cu(0) atomic percent are demonstrated for these reduction reactions; furthermore, a protocol for correlating material parameters to catalytic efficiency is presented and the importance of catalyst design for these broadly utilized probe reactions is highlighted.

Enhanced Photocatalytic Water Splitting of SrTiO3 Perovskite through Cobalt Doping: Experimental and Theoretical DFT Understanding

Throughout extensive research endeavors, SrTiO3 has emerged as a promising photocatalytic material for utilizing solar energy and facilitating hydrogen production via water splitting. Yet, the pursuit of enhanced efficiency and amplified hydrogen generation has prompted researchers to delve into the realm of advanced doping strategies. In this work, using experimental characteristics and DFT calculations, we studied the effect of cobalt substitution on the structural, electronic, optical, and magnetic properties as well as the photocatalytic activity of SrTi1-xCoxO3-δ (x = 0, 0.125, 0.25, 0.375, and 0.5) perovskites. The samples were successfully prepared by using the solid-state reaction method. Based on X-ray diffraction and the Rietveld refinement method, the elaborated samples were shown to preserve the absorption range up to the visible region. Moreover, the position of band edge levels after cobalt doping becomes more appropriate for water splitting. Our findings report that all cobalt-doped compounds exhibit good photocatalytic activities and could be used as suitable photocatalyst materials for hydrogen production.