Junjuan Yang

Bio: Junjuan Yang is an academic researcher from Chinese Academy of Sciences. The author has contributed to research in topics: Catalysis & Formate. The author has an hindex of 2, co-authored 5 publications receiving 24 citations.

Selective hydrogenation of 5-(hydroxymethyl)furfural to 5-methylfurfural over single atomic metals anchored on Nb2O5.

Abstract: 5-Methylfurfural (MF) is a very useful chemical. Selective hydrogenation of biomass platform molecule 5-(hydroxymethyl)furfural (HMF) to MF using H2 as the reducing agent is very attractive, but challenging because hydrogenation of C=O bond in HMF is more favourable than C-OH both kinetically and thermodynamically, and this route has not been realized. In this work, we prepare isolated single atomic catalysts (SACs) Pt1/Nb2O5-Ov, Pd1/Nb2O5-Ov, and Au1/Nb2O5-Ov, in which single metal atoms are supported on oxygen defective Nb2O5 (Nb2O5-Ov). It is discovered that the SACs can efficiently catalyze the hydrogenation of HMF to MF using H2 as the reducing agent with MF selectivity of >99% at complete conversion, while the selectivities of the metal nanocatalysts supported on Nb2O5 are very poor. A combination of experimental and density function theory (DFT) studies show that the unique features of the SACs for the reaction result from the cooperation of the Nb and Pt sites near the interface in the Pt1/Nb2O5-Ov. The Pt atoms are responsible for the activation of H2 and the Nb sites activate C-OH in the reaction. This work opens the way for producing MF by direct hydrogenation of biomass-derived HMF using H2 as the reductant.

CO 2 Hydrogenation to Formate Catalyzedby Ru Coordinated with a N,P-Containing Polymer

Abstract: Development of high-performance catalysts for carbon dioxide (CO2) hydrogenation is crucial for CO2 utilization. Herein, a heterogeneous catalyst for CO2 hydrogenation to formate was developed by c...

Copper/Carbon Heterogenous Interfaces for Enhanced Selective Electrocatalytic Reduction of CO2 to Formate.

Abstract: Electrochemical reduction of CO2 (CO2 RR) to formate is a promising route to prepare value-added chemical. Developing low-cost and efficient electrocatalysts with high product selectivity is still a grand challenge. Herein, a novel Cu anchored on hollow carbon spheres catalysts (HCS/Cu-x, x represents the mass of CuCl2 added in the system) is designed with controllable copper/carbon heterogenous interfaces. Rich copper/carbon heterogenous interfaces and hollow structure of optimized HCS/Cu-0.12 catalyst are beneficial to charge transmission. Compared with the CO2 RR occurred in aqueous electrolyte over Cu-based catalyst that has been reported to date, it exhibits highest formate Faradaic efficiency (FE) of 82.4% with a current density of 26 mA cm-2 and remarkable stability in a H-cell.

Production of Piperidine and δ-Lactam Chemicals from Biomass-Derived Triacetic Acid Lactone

Abstract: Piperidine and δ-Lactam chemicals have wide application, which are currently produced from fossil resource in industry. Production of this kind of chemicals from lignocellulosic biomass is of great importance, but is challenging and the reported routes give low yield. Herein, we demonstrate the strategy to synthesize 2-methyl piperidine ( MP ) and 6-methylpiperidin-2-one ( MPO ) from biomass-derived triacetic acid lactone ( TAL ) that is produced microbially from glucose. In this route, TAL was firstly converted into 4-hydroxy-6-methylpyridin-2(1H)-one ( HMPO ) through facile aminolysis, subsequently HMPO was selectively transformed into MP or MPO over Ru catalysts supported on beta zeolite (Ru/BEA-X, X is the molar ratio of Si to Al) via the tandem reaction. It was found that the yield of MP could reach 76.5% over Ru/BEA-60 in t -BuOH, and the yield of MPO could be 78.5% in dioxane. Systematic studies reveal that the excellent catalytic performance of Ru/BEA-60 was closely correlated with the cooperative effects between active metal and acidic zeolite with large pore geometries. The related reaction pathway was studied on the basis of control experiments.

Organic amine mediated cleavage of Caromatic–Cα bonds in lignin and its platform molecules

Abstract: The activation and cleavage of C–C bonds remains a critical scientific issue in many organic reactions and is an unmet challenge due to their intrinsic inertness and ubiquity. Meanwhile, it is crucial for the valorization of lignin into high-value chemicals. Here, we proposed a novel strategy to enhance the Caromatic–Cα bond cleavage by pre-functionalization with amine sources, in which an active amine intermediate is first formed through Markovnikov hydroamination to reduce the dissociation energy of the Caromatic–Cα bond which is then cleaved to form target chemicals. More importantly, this strategy provides a method to achieve the maximum utilization of the aromatic nucleus and side chains in lignin or its platform molecules. Phenols and N,N-dimethylethylamine compounds with high yields were produced from herbaceous lignin or the p-coumaric acid monomer in the presence of industrially available dimethylamine (DMA).

Heterogeneous catalysts for CO2 hydrogenation to formic acid/formate: from nanoscale to single atom

Abstract: Propelled by the vision of carbon-neutral energy systems, heterogeneous hydrogenation of CO2 to formic acid/formate, a liquid hydrogen carrier, has been intensively studied as a promising approach to realize renewable and decarbonized energy supply. In the present review, the state-of-the-art of heterogeneous catalysts for this process is comprehensively summarized. First, a brief description of the challenges associated with thermodynamics is provided. Major advancements on constructing efficient heterogeneous catalysts then constitute the main body of this review, mainly involving nanostructured and single atom catalysts based on noble metals. Special attention is paid to the relevant structure–activity correlations and mechanistic insights, which provide strong bases for rational catalyst design. Key factors related to catalytic activity are highlighted including metal dispersion, electron density, basic functionalities, and concerted catalysis of metal and basic sites. A summary and outlook is presented in the end. We believe that this review will inspire more novel research from the catalysis community to advance the design of innovative catalytic materials towards the ultimate sustainable energy sector with a closed carbon loop.

A unified view on catalytic conversion of biomass and waste plastics

Abstract: Originating from the desire to improve sustainability, producing fuels and chemicals from the conversion of biomass and waste plastic has become an important research topic in the twenty-first century. Although biomass is natural and plastic synthetic, the chemical nature of the two are not as distinct as they first appear. They share substantial structural similarities in terms of their polymeric nature and the types of bonds linking their monomeric units, resulting in close relationships between the two materials and their conversions. Previously, their transformations were mostly studied and reviewed separately in the literature. Here, we summarize the catalytic conversion of biomass and waste plastics, with a focus on bond activation chemistry and catalyst design. By tracking the historical and more recent developments, it becomes clear that biomass and plastic have not only evolved their unique conversion pathways but have also started to cross paths with each other, with each influencing the landscape of the other. As a result, this Review on the catalytic conversion of biomass and waste plastic in a unified angle offers improved insights into existing technologies, and more importantly, may enable new opportunities for future advances.

Green Carbon Science: Efficient Carbon Resource Processing, Utilization, and Recycling towards Carbon Neutrality

Abstract: Green carbon science is defined as the "study and optimization of the transformation of carbon-containing compounds and the relevant processes involved in the entire carbon cycle from carbon resource processing, carbon energy utilization, CO2 fixation, and carbon recycling to utilize carbon resources efficiently and minimize the net CO2 emission."[1] Green carbon science is related closely to carbon neutrality, and relevant fields have developed quickly in the last decade. In this Minireview, we propose the concept of carbon energy index, and the recent progress in petroleum refining, and the production of liquid fuels, chemicals, and materials using coal, methane, CO2 , biomass, and waste plastics is highlighted in combination with green carbon science. An outlook for these important fields is provided in the final section.