Zan Lian

Bio: Zan Lian is an academic researcher from Chinese Academy of Sciences. The author has contributed to research in topics: Catalysis & Dehydrogenation. The author has an hindex of 12, co-authored 26 publications receiving 437 citations. Previous affiliations of Zan Lian include University of Science and Technology of China.

Strong Electronic Coupling between Ultrafine Iridium–Ruthenium Nanoclusters and Conductive, Acid-Stable Tellurium Nanoparticle Support for Efficient and Durable Oxygen Evolution in Acidic and Neutral Media

Abstract: Proton exchange membrane water electrolysis (PEM-WE) has emerged as a promising technology for hydrogen production and shows substantial advantages over conventional alkaline water electrolysis. To...

Cyano group modified carbon nitride with enhanced photoactivity for selective oxidation of benzylamine

Abstract: Polymeric graphitic carbon nitride (g-C3N4) is a promising photocatalyst but suffers from the high recombination rate of photogenerated carriers. Many strategies for introducing active “sites”, such as heteroatom doping and defect creation, which can hinder recombination by capturing the separated electrons or holes, have been developed to solve the problem. As a polymeric organic material, it is possible to alter the electron structure and improve the charge separation by introducing organic groups with different electronegativities or conjugation properties to the side chains. Herein, we report a facile and efficient C N group modification strategy using the thermal condensation of the thiocyanuric acid (TA) precursor. The sulfur content in the precursor forms C N S and then transforms to C N. The C N group introduced catalyst exhibits enhanced light absorption and a low carrier recombination rate based on optical and photoelectrical measurements. This is due to the formation of a C N group related midgap state between the bandgap of g-C3N4, according to a density functional theory (DFT) calculation. The C N groups can also loosen the stacking texture of g-C3N4 and result in a thinner layer structure during the post-thermal treatment, which can shorten the distance of photogenerated carrier transfer from the bulk to the surface. The C N group introduced photocatalyst is efficient for the selective oxidation of benzylamine to imine, even under green light irradiation. This result demonstrates that the introduction of an electron rich conjugation group such as C N into the edge chain of polymeric carbon nitride is efficient for better photoactivity.

Revealing the Janus Character of the Coke Precursor in the Propane Direct Dehydrogenation on Pt Catalysts from a kMC Simulation

Abstract: As the commercial catalyst in the propane direct dehydrogenation (PDH) reaction, one of the biggest challenges of Pt catalysts is coke formation, which severely reduces activity and stability. In this work, a first-principles DFT-based kinetic Monte Carlo simulation (kMC) is performed to understand the origin of coke formation, and an effective method is proposed to curb coke. The conventional DFT calculations give a complete description of the reaction pathway of dehydrogenation to propylene, deep dehydrogenation, and C–C bond cracking. The rate-limiting step is identified as the dissociative adsorption of propane. Moreover, a comparison between different exchange-correlation functionals indicates the importance of van der Waals corrections for the adsorption of propane and propylene. The lateral interactions between the surface adsorbates are significant, which implies that mean field microkinetic modeling might not adequately describe the reaction process. There are two distinct stages in PDH, which ar...

Ti3C2Tx MXene Catalyzed Ethylbenzene Dehydrogenation: Active Sites and Mechanism Exploration from both Experimental and Theoretical Aspects

Abstract: Two-dimensional materials (such as graphene, MXenes) usually perform remarkably well as catalysts in comparison with their three-dimensional counterparts In this work, Ti3AlC2-derived Ti3C2Tx MXene (T = O, OH, F) was prepared and employed in the direct dehydrogenation of ethylbenzene A 92 μmol m–2 h–1 reactivity and a 40 h stability with almost no deactivation were observed, which is much better than those of the previously reported nanocarbon catalysts The graphene-like layered structure and the C–Ti–O termination groups induced by the preparation process were thought to account for the good catalytic performance of Ti3C2Tx MXene from both experimental and computational perspectives The discovery expands the application of two-dimensional MXenes and provides more choices in exploring high-activity catalysts for hydrocarbon dehydrogenation reactions

Atomic-Step Enriched Ruthenium–Iridium Nanocrystals Anchored Homogeneously on MOF-Derived Support for Efficient and Stable Oxygen Evolution in Acidic and Neutral Media

Abstract: Achieving an efficient and stable oxygen evolution reaction (OER) in an acidic or neutral medium is of paramount importance for hydrogen production via proton exchange membrane water electrolysis (...

Electrocatalysis for CO2 conversion: from fundamentals to value-added products

Abstract: The continuously increasing CO2 released from human activities poses a great threat to human survival by fluctuating global climate and disturbing carbon balance among the four reservoirs of the biosphere, earth, air, and water. Converting CO2 to value-added feedstocks via electrocatalysis of the CO2 reduction reaction (CO2RR) has been regarded as one of the most attractive routes to re-balance the carbon cycle, thanks to its multiple advantages of mild operating conditions, easy handling, tunable products and the potential of synergy with the rapidly increasing renewable energy (i.e., solar, wind). Instead of focusing on a special topic of electrocatalysts for the CO2RR that have been extensively reviewed elsewhere, we herein present a rather comprehensive review of the recent research progress, in the view of associated value-added products upon selective electrocatalytic CO2 conversion. We initially provide an overview of the history and the fundamental science regarding the electrocatalytic CO2RR, with a special introduction to the design, preparation, and performance evaluation of electrocatalysts, the factors influencing the CO2RR, and the associated theoretical calculations. Emphasis will then be given to the emerging trends of selective electrocatalytic conversion of CO2 into a variety of value-added products. The structure-performance relationship and mechanism will also be discussed and investigated. The outlooks for CO2 electrocatalysis, including the challenges and opportunities in the development of new electrocatalysts, electrolyzers, the recently rising operando fundamental studies, and the feasibility of industrial applications are finally summarized.

A Theory/Experience Description of Support Effects in Carbon-Supported Catalysts.

Abstract: The support plays an important role for supported metal catalysts by positioning itself as a macromolecular ligand, which conditions the nature of the active site and contributes indirectly but also sometimes directly to the reactivity. Metal species such as nanoparticles, clusters, or single atoms can be deposited on carbon materials for various catalytic reactions. All the carbon materials used as catalyst support constitute a large family of compounds that can vary both at textural and at structural levels. Today, the recent developments of well-controlled synthesis methodologies, advanced characterization techniques, and modeling tools allow one to correlate the relationships between metal/support/reactant at the molecular level. Based on these considerations, in this Review article, we wish to provide some answers to the question "How and why anchoring metal nanoparticles, clusters, or single atoms on carbon materials for catalysis?". To do this, we will rely on both experimental and theoretical studies. We will first analyze what sites are available on the surface of a carbon support for the anchoring of the active phase. Then, we will describe some important effects in catalysis inherent to the presence of a carbon-type support (metal-support interaction, confinement, spillover, and surface functional group effects). These effects will be commented on by putting into perspective catalytic results obtained in numerous reactions of thermal catalysis, electrocatalysis, or photocatalysis.

Recent Advances in Electrochemical CO2-to-CO Conversion on Heterogeneous Catalysts

Abstract: Electrochemical reduction of carbon dioxide (CO2 ) to fuels and chemicals provides a promising solution for renewable energy storage and utilization. Among the many possible reaction pathways, CO2 conversion to carbon monoxide (CO) is the first step in the synthesis of more complex carbon-based fuels and feedstocks, and holds great significance for the chemical industry. Herein, recent advances in heterogeneous catalysts for selective CO evolution from electrochemical reduction of CO2 are described. With Au catalysts as a paradigm, principles for catalyst design including size, morphology, and grain boundary densities tuning, surface modifications, as well as metal-support interaction are comprehensively summarized, which shed light on the development of other transition metal catalysts targeting efficient CO2 -to-CO conversion. In addition, recently emerged novel materials including transition metal single-atom catalysts, which present significantly different catalytic behaviors compared to their bulk counterparts and thus open up many unexpected opportunities, are summarized. Furthermore, the technical aspects with respect to large-scale production of CO are presented, focusing on the full-cell design and implementation. Finally, short comments related to the future direction of real-word CO2 electrolysis for CO supply are provided in terms of catalyst optimization and technical breakthrough.

Theoretical Understandings of Graphene-based Metal Single-Atom Catalysts: Stability and Catalytic Performance.

Abstract: Research on heterogeneous single-atom catalysts (SACs) has become an emerging frontier in catalysis science because of their advantages in high utilization of noble metals, precisely identified active sites, high selectivity, and tunable activity. Graphene, as a one-atom-thick two-dimensional carbon material with unique structural and electronic properties, has been reported to be a superb support for SACs. Herein, we provide an overview of recent progress in investigations of graphene-based SACs. Among the large number of publications, we will selectively focus on the stability of metal single-atoms (SAs) anchored on different sites of graphene support and the catalytic performances of graphene-based SACs for different chemical reactions, including thermocatalysis and electrocatalysis. We will summarize the fundamental understandings on the electronic structures and their intrinsic connection with catalytic properties of graphene-based SACs, and also provide a brief perspective on the future design of efficient SACs with graphene and graphene-like materials.