Periodic Open Cellular Raney‐Copper Catalysts Fabricated via Selective Electron Beam Melting

Abstract

Herein, the possibility of generating Raney‐Copper catalysts with high geometric complexity is demonstrated. For this, periodic open cellular structures (POCS) composed of a highly brittle Al–Cu alloy containing 29.4 at% copper are fabricated by selective electron beam melting (SEBM) for application in chemical reaction engineering. After selective leaching of aluminum in an NaOH solution, the POCS show a core–shell structure with a nanoporous copper surface layer and a solid core. The fabrication and dealloying processes as well as the microstructure are studied. Moreover, the SEBM‐processed Raney‐type copper catalysts show a high catalytic activity in methanol synthesis.

3D-Printed Raney-Cu POCS as Promising New Catalysts for Methanol Synthesis

“…A layer thickness of 100 µm is melted with a line energy of 1.3 J mm −1 and a scan velocity of 0.23 m s −1 . The individual struts of the POCS showed a strut thickness of 0.9 ± 0.1 mm and 1.3 ± 0.1 mm, respectively [17].…”

“…All of these studies (Figure 4a-d) show, that the leaching process progresses much more rapidly in NaOH solution than in the NaOH/Na2Zn(OH)4 solution. After identical of a POCS; and (d) as-built structure (left) and mechanically post-processed POCS to methanol reactor dimension (right), adapted from [17].…”

“…The formation of DME is favoured at higher temperatures and higher residence times (i.e., lower volume flows). A detailed description of the fabrication of the Raney-Cu structures has already been published [17] and is only briefly summarized here. For all Cu 50 Al 50 structures, an inert gas atomized pre-alloyed Cu 50 Al 50 powder with a nominal composition of 50 wt% copper, a balance of aluminum (ECKA Granules GmbH, Fürth, Germany), and a particle size distribution between 45 and 105 µm was processed.…”

“…These structures facilitate heat management by providing solid, large area connections to the reactor wall surface while simultaneously providing a sufficiently large internal surface area for efficient catalysis. POCS with a Raney-Cu surface can be fabricated by additive manufacturing techniques (e.g., 3D-printing), specifically by Powder Bed Fusion by Electron Beam (PBF-EB) of a suitable alloy (Al 50 Cu 50 ) and subsequent chemical leaching of the less noble component (Al) [17]. The PBF-EB technique allows the fabrication of complex open cellular structures, which after leaching the inactive component from the outer shell retain a solid core of the original alloy to provide mechanical stability and to facilitate heat transfer [16][17][18].…”

Skeletal Nickel Catalyst for the Methanation Reaction Developed by Laser-Engineered Net-Shaping Technology

“…Albert et al [28] used the laser metal deposition technique to prepare a Raney copper catalyst with low product selectivity. Wasserscheid et al [29] prepared Raney copper with an open periodic structure by the selective electron-beam melting technique, which effectively reduced the bed pressure drop.…”