Xiao Jiang

Bio: Xiao Jiang is an academic researcher from Oak Ridge National Laboratory. The author has contributed to research in topics: Catalysis & Dehydrogenation. The author has an hindex of 24, co-authored 43 publications receiving 2057 citations. Previous affiliations of Xiao Jiang include Dalian University of Technology & Pennsylvania State University.

Recent Advances in Carbon Dioxide Hydrogenation to Methanol via Heterogeneous Catalysis.

Abstract: The utilization of fossil fuels has enabled an unprecedented era of prosperity and advancement of well-being for human society. However, the associated increase in anthropogenic carbon dioxide (CO2) emissions can negatively affect global temperatures and ocean acidity. Moreover, fossil fuels are a limited resource and their depletion will ultimately force one to seek alternative carbon sources to maintain a sustainable economy. Converting CO2 into value-added chemicals and fuels, using renewable energy, is one of the promising approaches in this regard. Major advances in energy-efficient CO2 conversion can potentially alleviate CO2 emissions, reduce the dependence on nonrenewable resources, and minimize the environmental impacts from the portions of fossil fuels displaced. Methanol (CH3OH) is an important chemical feedstock and can be used as a fuel for internal combustion engines and fuel cells, as well as a platform molecule for the production of chemicals and fuels. As one of the promising approaches, thermocatalytic CO2 hydrogenation to CH3OH via heterogeneous catalysis has attracted great attention in the past decades. Major progress has been made in the development of various catalysts including metals, metal oxides, and intermetallic compounds. In addition, efforts are also put forth to define catalyst structures in nanoscale by taking advantage of nanostructured materials, which enables the tuning of the catalyst composition and modulation of surface structures and potentially endows more promising catalytic performance in comparison to the bulk materials prepared by traditional methods. Despite these achievements, significant challenges still exist in developing robust catalysts with good catalytic performance and long-term stability. In this review, we will provide a comprehensive overview of the recent advances in this area, especially focusing on structure-activity relationship, as well as the importance of combining catalytic measurements, in situ characterization, and theoretical studies in understanding reaction mechanisms and identifying key descriptors for designing improved catalysts.

A short review of recent advances in CO2 hydrogenation to hydrocarbons over heterogeneous catalysts

Abstract: CO2 hydrogenation to hydrocarbons is a promising way of making waste to wealth and energy storage, which also solves the environmental and energy issues caused by CO2 emissions Much efforts and research are aimed at the conversion of CO2 via hydrogenation to various value-added hydrocarbons, such as CH4, lower olefins, gasoline, or long-chain hydrocarbons catalyzed by different catalysts with various mechanisms This review provides an overview of advances in CO2 hydrogenation to hydrocarbons that have been achieved recently in terms of catalyst design, catalytic performance and reaction mechanism from both experiments and density functional theory calculations In addition, the factors influencing the performance of catalysts and the first C–C coupling mechanism through different routes are also revealed The fundamental factor for product selectivity is the surface H/C ratio adjusted by active metals, supports and promoters Furthermore, the technical and application challenges of CO2 conversion into useful fuels/chemicals are also summarized To meet these challenges, future research directions are proposed in this review

Bimetallic Pd–Cu catalysts for selective CO2 hydrogenation to methanol

Abstract: This paper reports on novel Pd–Cu bimetallic catalysts for selective CO2 hydrogenation to methanol. Strong synergistic effect on promoting methanol formation was observed over amorphous silica supported Pd–Cu bimetallic catalysts when the Pd/(Pd + Cu) atomic ratios lied in the range of 0.25–0.34. The methanol formation rate over Pd(0.25)–Cu/SiO2 was two times higher than the simple sum of those over monometallic Cu and Pd catalysts. The Pd–Cu bimetallic catalysts were characterized by X-ray diffraction, transmission electron microscopy, scanning transmission electron microscopy coupled with energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and hydrogen temperature-programmed desorption. Detailed characterization results demonstrated the importance of two well-dispersed Pd–Cu alloy particles (PdCu and PdCu3) for the observed methanol promotion over Pd–Cu bimetallic catalysts. Similar bimetallic promotion was also observed for Pd–Cu catalysts supported on uniform mesoporous MCM-41, SBA-15 and MSU-F. Conversion-selectivity profile of the Pd–Cu/SiO2 catalyst suggested that CO2 was a primary carbon source for methanol synthesis at lower CO2 conversion, and byproduct CO contributed at higher CO2 conversion within the conversion range examined.

ZrO2 support imparts superior activity and stability of Co catalysts for CO2 methanation

Abstract: Screening of various supports reveals that Co catalysts supported on ZrO2 and Al2O3 show good initial activity for CO2 methanation. Co/ZrO2 and Co/Al2O3 catalysts prepared by impregnation with different metal loadings were further examined comparatively. The 10Co/ZrO2 catalyst showed high activity with CO2 conversion of 92.5% and CH4 selectivity of 99.9% without deactivation after 300 h time on stream (TOS). However, the 10Co/Al2O3 catalyst gave a lower CO2 conversion of 77.8% which decreased to 38.6% after 300 h TOS. The catalysts were characterized by STEM/EDS (scanning transmission electron microscopy/energy-dispersive X-ray spectroscopy), in situ XRD(X-ray diffractometer), H2-TPR(temperature programmed reduction), XPS (X-ray photoelectron spectroscopy), chemisorption of H2, CO, CH4, CO2 and NH3-TPD (temperature programmed desorption). Re-dispersion of Co species on the ZrO2 support during reduction by H2 was observed by STEM/EDS. New Co-Zr phase formed on the Co-ZrO2 interface was directly observed by TEM for the first time; the Co/ZrO2 catalyst exhibited high stability with high activity for CO2 conversion. In situ XRD, H2-TPR and XPS results indicate the promoting effect of ZrO2 on the reduction of Co3O4 to Co metal along with the negative effect of Al2O3. The oxygen vacancies on the ZrO2 detected by XPS may help to activate CO2 and H2O and resist deactivation. Co/Al2O3 catalyst deactivates rapidly due to coke deposition and spinel formation.

Symmetric and unsymmetric donor functionalization. comparing structural and spectral benefits of chromophores for dye-sensitized solar cells

Abstract: A series of organic chromophores have been synthesized in order to investigate the benefits of structural versus spectral properties as well as the absorption properties and solar cell performance with unsymmetrically introduced substituents in the chromophore. Exceptionally high open-circuit voltage, Voc, was found for the symmetrical structurally benefited dye, which also gave the best overall solar cell performance.

Kirk-Othmer Encyclopedia of Chemical Technology数据库介绍及实例

Abstract: 介绍了Kirk—Othmer Encyclopedia of Chemical Technology（化工技术百科全书）（第五版）电子图书网络版数据库，并对该数据库使用方法和检索途径作出了说明，且结合实例简单地介绍了该数据库的检索方法。

Carbon capture and conversion using metal–organic frameworks and MOF-based materials

Abstract: Rapidly increasing atmospheric CO2 concentrations threaten human society, the natural environment, and the synergy between the two. In order to ameliorate the CO2 problem, carbon capture and conversion techniques have been proposed. Metal–organic framework (MOF)-based materials, a relatively new class of porous materials with unique structural features, high surface areas, chemical tunability and stability, have been extensively studied with respect to their applicability to such techniques. Recently, it has become apparent that the CO2 capture capabilities of MOF-based materials significantly boost their potential toward CO2 conversion. Furthermore, MOF-based materials’ well-defined structures greatly facilitate the understanding of structure–property relationships and their roles in CO2 capture and conversion. In this review, we provide a comprehensive account of significant progress in the design and synthesis of MOF-based materials, including MOFs, MOF composites and MOF derivatives, and their application to carbon capture and conversion. Special emphases on the relationships between CO2 capture capacities of MOF-based materials and their catalytic CO2 conversion performances are discussed.

Status and perspectives of CO2 conversion into fuels and chemicals by catalytic, photocatalytic and electrocatalytic processes

Abstract: This review highlights recent developments and future perspectives in carbon dioxide usage for the sustainable production of energy and chemicals and to reduce global warming. We discuss the heterogeneously catalysed hydrogenation, as well as the photocatalytic and electrocatalytic conversion of CO2 to hydrocarbons or oxygenates. Various sources of hydrogen are also reviewed in terms of their CO2 neutrality. Technologies have been developed for large-scale CO2 hydrogenation to methanol or methane. Their industrial application is, however, limited by the high price of renewable hydrogen and the availability of large-volume sources of pure CO2. With regard to the direct electrocatalytic reduction of CO2 to value-added chemicals, substantial advances in electrodes, electrolyte, and reactor design are still required to permit the development of commercial processes. Therefore, in this review particular attention is paid to (i) the design of metal electrodes to improve their performance and (ii) recent developments of alternative approaches such as the application of ionic liquids as electrolytes and of microorganisms as co-catalysts. The most significant improvements both in catalyst and reactor design are needed for the photocatalytic functionalisation of CO2 to become a viable technology that can help in the usage of CO2 as a feedstock for the production of energy and chemicals. Apart from technological aspects and catalytic performance, we also discuss fundamental strategies for the rational design of materials for effective transformations of CO2 to value-added chemicals with the help of H2, electricity and/or light.

State of the Art and Prospects in Metal-Organic Framework (MOF)-Based and MOF-Derived Nanocatalysis.

Abstract: Metal-organic framework (MOF) nanoparticles, also called porous coordination polymers, are a major part of nanomaterials science, and their role in catalysis is becoming central. The extraordinary variability and richness of their structures afford engineering synergies between the metal nodes, functional linkers, encapsulated substrates, or nanoparticles for multiple and selective heterogeneous interactions and activations in these MOF-based nanocatalysts. Pyrolysis of MOF-nanoparticle composites forms highly porous N- or P-doped graphitized MOF-derived nanomaterials that are increasingly used as efficient catalysts especially in electro- and photocatalysis. This review first briefly summarizes this background of MOF nanoparticle catalysis and then comprehensively reviews the fast-growing literature reported during the last years. The major parts are catalysis of organic and molecular reactions, electrocatalysis, photocatalysis, and views of prospects. Major challenges of our society are addressed using these well-defined heterogeneous catalysts in the fields of synthesis, energy, and environment. In spite of the many achievements, enormous progress is still necessary to improve our understanding of the processes involved beyond the proof-of-concept, particularly for selective methane oxidation, hydrogen production, water splitting, CO2 reduction to methanol, nitrogen fixation, and water depollution.

Design of Organic Dyes and Cobalt Polypyridine Redox Mediators for High-Efficiency Dye-Sensitized Solar Cells

Abstract: Dye-sensitized solar cells (DSCs) with cobalt-based mediators with efficiencies surpassing the record for DSCs with iodide-free electrolytes were developed by selecting a suitable combination of a cobalt polypyridine complex and an organic sensitizer. The effect of the steric properties of two triphenylamine-based organic sensitizers and a series of cobalt polypyridine redox mediators on the overall device performance in DSCs as well as on transport and recombination processes in these devices was compared. The recombination and mass-transport limitations that, previously, have been found to limit the performance of these mediators were avoided by matching the properties of the dye and the cobalt redox mediator. Organic dyes with higher extinction coefficients than the standard ruthenium sensitizers were employed in DSCs in combination with outer-sphere redox mediators, enabling thinner TiO2 films to be used. Recombination was reduced further by introducing insulating butoxyl chains on the dye rather than...