Xiang Tan

Bio: Xiang Tan is an academic researcher from Chinese Ministry of Education. The author has contributed to research in topics: Biodiesel production & Composite number. The author has an hindex of 1, co-authored 3 publications receiving 8 citations. Previous affiliations of Xiang Tan include Guizhou University.

Sulfonic acid-functionalized heterogeneous catalytic materials for efficient biodiesel production: A review

Abstract: The development of social productive forces leads to the increasing consumption of fossil fuels. However, the burning of traditional fossil fuels releases huge amounts of carbon emissions into the atmosphere, resulting in drastically increased global surface temperatures, and hence, global warming and abnormal climate change. Biodiesel, which can be produced by (trans)esterification of bio-oils using solid acid catalysts, is recognized as renewable and clean energy, alternative to fossil-derived diesel, and it can meet society's requirements. This review describes the catalytic conversion of bio-derived oils into biodiesel using various sulfonic acid-functionalized heterogeneous catalytic materials that show higher catalytic efficiency and superior recyclability. Besides, various methods of biodiesel preparation and the appropriate design and preparation of robust and efficient catalytic materials for biodiesel production were provided. Finally, the mechanisms of different catalytic esterification and transesterification reactions for biodiesel synthesis, the relevant reaction kinetic models, and techno-economic analysis of biodiesel production were critically discussed in this review.

Single-Atom Catalysts-Enabled Reductive Upgrading of CO2

Abstract: Single‐atom catalysts (SACs) have attracted extensive attention since their emergence. During the single‐atomic catalytic process, the “active center” exists in the form of atomical monodispersion, with nearly 100 % utilization of metal atoms. Uniform and atomically dispersed catalytic centers give SACs pronounced reaction activity and chemical selectivity. Here, we review the development processes, synthetic strategies, characterization methods, and applications of SACs in CO2 reductive upgrading. Also, a comparison of SACs with conventional heterogeneous catalysts in catalytic CO2 reduction is made and discussed. SACs have built a bridge between homogeneous and heterogeneous catalysis and have the advantages of both, showing a broad prospect in the field of catalysis.

Sulfonic acid functionalized graphitic carbon nitride as solid acid–base bifunctional catalyst for Knoevenagel condensation and multicomponent tandem reactions

Abstract: Rational design and development of acid–base bifunctional heterogeneous catalysts for organic synthesis is a tough process. A highly efficient, non-toxic, metal-free, low-cost, acid–base bifunctional sulfonated graphitic carbon nitride (S-g-C3N4) catalyst has been developed. The as-synthesized S-g-C3N4 catalyst exhibits high catalytic potential towards Knoevenagel condensation and sequential tandem reactions. The as-synthesized catalyst was developed by sulfonation of graphitic carbon nitride (g-C3N4). The sulfonation leads to surface functionalization of –SO3H groups onto the catalyst surface. These –SO3H groups impart acidic nature to the S-g-C3N4 catalyst along with the preexisting basic nature of the catalyst due to the presence of N-containing moieties. These dual acid–base functionalities behave as active sites for the sequential catalytic reactions to occur. The S-g-C3N4 catalyst exhibits high turnover numbers (TON) and high yields in shorter reaction time at optimum conditions of temperature which demonstrates the high catalytic activity of the S-g-C3N4 nanosheets. The corresponding green metrics parameters were also calculated, in addition to demonstrating the excellent catalyst recyclability and reusability. The as-synthesized S-g-C3N4 catalyst provides a metal-free, sustainable and green approach for utilizing acid–base bifunctional catalysts for sequential organic synthesis.

Single-Atom Catalysts (SACs) for Photocatalytic CO2 Reduction with H2 O: Activity, Product Selectivity, Stability, and Surface Chemistry.

Abstract: In recent years, single-atom catalysts (SACs) have attracted the interest of researchers owing to their suitability for various catalytic applications. For instance, their optoelectronic features, site-specific activity, and cost-effectiveness make SACs ideal for photocatalytic CO2 reduction. The activity, product selectivity, and photostability of SACs depend on various factors such as the nature of the metal/support material, the interaction between the metal atoms and support, light-harvesting ability, charge separation behavior, CO2 adsorption ability, active sites, and defects. Consequently, it is necessary to investigate these factors in depth to elucidate the working principle(s) of SACs for catalytic applications. Herein, the recent progress in the development of SACs for photocatalytic CO2 reduction with H2 O is reviewed. First, a brief overview of CO2 photoreduction and SACs for CO2 conversion is provided. Several synthesis strategies and useful techniques for characterizing SACs employed in heterogeneous catalysis are then described. Next, the challenges of SACs for photocatalytic CO2 reduction and related optimization strategies, in terms of activity, product selectivity, and stability, are explored. The progress in the development of noble metal- and transition metal-based SACs and dual-SACs for photocatalytic CO2 reduction is discussed. Finally, the prospects of SACs for CO2 reduction are considered.