Facile one-pot synthesis and characterization of nickel supported on hierarchically porous carbon

Significance Statement

Fixed bed catalysts are widely used for large-scale chemicals production.  Many such catalysts consist of metal (often a precious metal) particles spread over a support such as silica, alumina or carbon.  How well a catalyst works depends upon how well distributed the metal particles are over the support, the amount of accessible surface area, how quickly reactants get transported to the surface of the catalyst and how quickly products get transported away from the catalyst surface, and how effectively heat is transported to and from the metal particles.  Also critical is how long the catalyst functions before it needs to be replaced.

Hierarchically porous supports have networks of micrometer scale pores that provide efficient transport of reactants and products into and out of the catalyst, coupled to nanometer scale pores that provide large surface area.  The micrometer scale pores are expected to make the catalyst more tolerant to deactivation by clogging.  Carbon is a cheap and renewable material that has good chemical stability and provides good heat transfer.  Nickel is an earth abundant metal that is considerably cheaper than precious metals such as palladium and platinum which often widely used in catalysis.  By combining appropriate precursors of nickel and carbon in a single solution the synthesis is expected to be significantly cheaper than for existing processes for making carbon supported catalysts.  It is also likely that the catalyst produced by this new process will have significantly different properties, as a number of processing steps that impact the final catalytic properties are avoided.  Recent work on biomass conversions is confirming that the catalytic properties are different and advantageous for some processes.

Although the work reported is for synthesis of a nickel containing catalyst it is believed that the process will be a relatively general method that can readily be extended to other transition metal containing catalysts.

The work has been sufficiently promising that The University of Alabama has filed a preliminary United States patent on this class of materials.

The work potentially has broader impact in the area of monolithic microreactors.  These are reactors are of considerable interest for fine chemicals production particularly pharmaceuticals where there the better quality control available from continuous processes has significant advantages.  The synthesis reported can readily produce monoliths (i.e. single pieces) of 2-20 mm diameter and lengths to 20 cm.  

Facile one-pot synthesis and characterization of nickel supported on hierarchically porous carbon. Advances in Engineering

About the author

Professor Martin G. Bakker was trained as a physical chemist and joined the chemistry faculty of The University of Alabama in 1990.  His research efforts span spectroscopy, radiation and photochemistry.  His current research interest is in the areas of materials chemistry applied to separations, catalysis, and energy storage.  His specific interests have been in areas of self-assembly and self-organization and how these processes can be used to produce hierarchically porous materials, those containing pores at multiple length scales, and applications of such hierarchically porous materials.  

About the author

Dr. Trupti V. Kotbagi has masters in Inorganic Chemistry and a Ph. D. in heterogeneous catalysis and currently working as postdoctoral fellow at the University of Alabama. Her research interests lie in core heterogeneous catalysis; material synthesis and characterization, design and building of flow reactors. Her specific interests are green catalysis involving synthesis of metal/metal oxide supported on hierarchically porous supports as heterogeneous catalysts for the transformations of bio-derived compounds to value added chemicals under batch and flow conditions.

Journal Reference

Materials Research Bulletin, Volume 73, January 2016, Pages 204-210.

Trupti V. Kotbagi, Yasemin Hakat, Martin G. Bakker

Department of Chemistry, The University of Alabama, Tuscaloosa, Al 35487-0336, United States

Abstract

Described is a novel, facile route for the synthesis of nickel supported on hierarchically porous carbon (Ni/HPC) using a one-pot co-gelation sol–gel method. Ni/HPC with varying nickel loadings (0.5, 1, 2.5 and 5 wt% Ni) were synthesized and the materials characterized by nitrogen physisorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) and Raman spectroscopies. The results show a three-dimensional network of disordered carbon with fine nickel nanoparticles of sizes ranging from 8 nm to 13 nm at 0.5 wt% Ni loading which gradually increased with increase in the Ni loading. The carbon structure was retained at the macropore level, but not at the mesoscale where the ordered mesopores were lost on nickel addition. The nickel nanoparticles were observed to grow on the surface of the ligaments. This may make them particularly suitable for low pressure Ni-catalyzed organic transformations e.g., hydrogenations, C–C coupling, C-heteroatom coupling, etc

Go To Materials Research Bulletin

 

Check Also

Computational Insights into High-Pressure Equilibria of Supercritical Gases in Ammonia - Advances in Engineering

Computational Insights into High-Pressure Equilibria of Supercritical Gases in Ammonia