Identification of Non-Precious Metal Alloy Catalysts for Selective Hydrogenation of Acetylene

Abstract

The removal of trace acetylene from ethylene is performed industrially by palladium hydrogenation catalysts (often modified with silver) that avoid the hydrogenation of ethylene to ethane. In an effort to identify catalysts based on less expensive and more available metals, density functional calculations were performed that identified relations in heats of adsorption of hydrocarbon molecules and fragments on metal surfaces. This analysis not only verified the facility of known catalysts but identified nickel-zinc alloys as alternatives. Experimental studies demonstrated that these alloys dispersed on an oxide support were selective for acetylene hydrogenation at low pressures.

Major Successes of Theory-and-Experiment-Combined Studies in Surface Chemistry and Heterogeneous Catalysis

“…With the help of these relations and the chemisorption model, catalytic properties of alloy combinations can be The calculated turnover rates as a function of the chemisorption energies of nitrogen on several metal and alloy surfaces. This chemisorption energy dependence of the reaction rate clearly demonstrates the Sabatier's principle investigated computationally in the search for the low-cost yet highly activity and selective catalysts [27,[74][75][76][77][78][79].…”

“…However, the proposed alloy catalysts are not necessarily stable under harsh reaction conditions, especially, when these catalysts are in the form of nanoparticles. On the one hand, in order to optimize the reactivity and selectivity of alloy nanoparticle, certain surface composition is usually required [22,27,75]. On the other hand, the surface composition of alloy nanoparticles may change dramatically with the reaction conditions as shown by an ambient pressure XPS study on bimetallic nanoparticles carried out recently at Berkeley [84].…”

“…His contributions to the theories of surface chemical bonding and catalytic reaction over the past 30 years lead to a giant leap forward in our molecular level understanding of surface chemistry and heterogeneous catalysis [12][13][14][15][16][17][18][19][20][21]. Of course, his achievement is a result of his exceptional expertise in theoretical chemistry, but, from the point of view of an experimentalist, the more important factors perhaps are his willingness to work closely with experimentalists and his ability to grasp the essence of experimental development [22][23][24][25][26][27][28].…”

Metal Oxide‐Supported Platinum Overlayers as Proton‐Exchange Membrane Fuel Cell Cathodes

“…Such relationships are indeed very useful, since only few parameters need to be determined to get the overall activity prediction. The use of DFT calculations has thus paved a way to numerous screening studies, which have pinpointed better catalytic materials for a number of reactions [10,49,50]. More specifically in the case of the ORR, the oxygen binding energy was found to be a single descriptor determining the overall activity [45].…”

Descriptor‐Based Analysis Applied to HCN Synthesis from NH3 and CH4

“…[1, 2] Recent developments in methodology and computer technology as well as the establishment of a descriptor-based approach for the analysis of reaction mechanisms and trends across the periodic table allow for the fast screening for new catalytic materials and have lead to first examples of computational discoveries of new materials. [3][4][5][6][7][8] The underlying principles of the descriptor-based approach are the existence of relations between the surface electronic structure, adsorption energies and activation barriers that result in volcanoshaped activity plots as function of simple descriptors, such as atomic binding energies or the d-band center. [1,6,[9][10][11][12][13][14][15][16][17] Linear scaling relations have been established between the adsorption energies of hydrogen-containing molecules such as CH x , NH x , OH x and SH x and the C, N O and S adsorption energies on transition-metal surfaces.…”