Stable amorphous georgeite as a precursor to a high-activity catalyst

DOI: 10.1038/nature16935
PMID: 26878237

Authors: Simon Kondrat (Cardiff Catalysis Institute, Cardiff University) , Paul J. Smith (Cardiff Catalysis Institute, Cardiff University) , Peter Wells (University College London) , Philip Chater (Diamond Light Source) , James H. Carter (Cardiff Catalysis Institute, Cardiff University) , David J Morgan (Cardiff University) , Elisabetta M. Fiordaliso (Technical University of Denmark) , Jakob B. Wagner (Technical University of Denmark) , Tom Davies (Cardiff Catalysis Institute) , Li Lu (Lehigh University) , Jonathan K. Bartley (Cardiff Catalysis Institute, Cardiff University) , Stuart H. Taylor (Cardiff Catalysis Institute, Cardiff University) , Michael S. Spencer (Cardiff Catalysis Institute, Cardiff University) , Christopher J. Kiely (Lehigh University) , Gordon J. Kelly (Johnson Matthey) , Colin W. Park (Johnson Matthey) , Matthew Rosseinsky (University of Liverpool) , Graham J. Hutchings (Cardiff Catalysis Institute, Cardiff University)
Co-authored by industrial partner: Yes

Type: Journal Paper
Journal: Nature

State: Published (Approved)
Published: February 2016
Diamond Proposal Number(s): 8071

Abstract: Copper and zinc form an important group of hydroxycarbonate minerals that include zincian malachite, aurichalcite, rosasite and the exceptionally rare and unstable—and hence little known and largely ignored1—georgeite. The first three of these minerals are widely used as catalyst precursors2, 3, 4 for the industrially important methanol-synthesis and low-temperature water–gas shift (LTS) reactions5, 6, 7, with the choice of precursor phase strongly influencing the activity of the final catalyst. The preferred phase2, 3, 8, 9, 10 is usually zincian malachite. This is prepared by a co-precipitation method that involves the transient formation of georgeite11; with few exceptions12 it uses sodium carbonate as the carbonate source, but this also introduces sodium ions—a potential catalyst poison. Here we show that supercritical antisolvent (SAS) precipitation using carbon dioxide (refs 13, 14), a process that exploits the high diffusion rates and solvation power of supercritical carbon dioxide to rapidly expand and supersaturate solutions, can be used to prepare copper/zinc hydroxycarbonate precursors with low sodium content. These include stable georgeite, which we find to be a precursor to highly active methanol-synthesis and superior LTS catalysts. Our findings highlight the value of advanced synthesis methods in accessing unusual mineral phases, and show that there is room for exploring improvements to established industrial catalysts.

Subject Areas: Chemistry


Instruments: B18-Core EXAFS , I15-Extreme Conditions

Other Facilities: APS