New 3D-Printable Industrial Catalyst Could Help Turn Waste Products into Valuable Fuel

Professor Yan Li with PhD student Ya Tang, first author on the study, in Li's material design lab. (Photo by Catha Mayor)

The study, published in the Nature Portfolio journal Advanced Manufacturing, presents a method and formulation that not only addresses geometric constraints, but also ensures uniformity of composition and structural integrity throughout the printed catalyst.

"Currently, we can process 10 pounds of plastic to yield one gallon of fuel," said Dartmouth Engineering Associate Professor Yan Li, co-corresponding author on the study. "If we want to increase this yield, we need a better catalyst."

Most conventional catalysts look like pellets or beads. "This shape creates a lot of resistance when gas reactants try to pass through," said Li. "But with our 3D-printed open-cell architecture, it's easier for the reactants to go through, and as a result, we get a more effective chemical reaction to increase the fuel yield. The geometry makes a huge difference."

Li further explained that optimal geometry increases processing speed as well as available surface area without losing mechanical strength. This is important because catalysts must operate in high-heat, high-pressure environments.

Although today's advanced 3D printing technology is an ideal method of fabricating the best shape, this only works if the catalyst material can be pushed through the printer nozzle smoothly and evenly. The collaborative study also addressed this challenge, and their unique formulation of catalyst particles blended with a binder solution has resulted in a provisional patent.

First author and PhD student Ya Tang holds a sample of the printed catalyst. (Photo by Catha Mayor)

"Our resin can be pushed through very smoothly," said Li. "We achieved both high concentration and smooth 3D printing without particles sinking to the bottom—a problem called sedimentation." Li explained that sedimentation is especially problematic for large-scale 3D printing operations, which require a formula with long-term stability. "Our formula achieves that, which makes commercialization much easier," she said.

The study's first author, Dartmouth Engineering PhD student Ya Tang, was recruited by Oak Ridge National Lab to work on the problem during an internship there. "They said, 'We have a digital light processing printer, and you have experience with a printer. Even though the technology is different, maybe you know how to do that,'" recounted Tang. "I said, 'Yeah, I'll try.'"

Tang did try, and succeeded in finding the right formula. "My favorite part was doing the iteration," he said. "3D-printing formulas require different binders and powders and processing temperatures, and also mixing techniques. So we tried a lot of things."

Tang continued, "You never know what's going to happen, but it's always exciting to find something that really works and really can change the world."