Trevor Best and Suman Khatiwada were working in the oil and gas R&D industry in Houston when they began searching for game-changing start-up ideas that could significantly reduce greenhouse gas emissions. The partners came across an intriguing plasmonic photocatalytic technology right next door at Rice University. The technology uses light instead of heat energy to slash emissions produced in manufacturing fuels and fertilizers.
Four years later, after founding Syzygy Plasmonics with investments from MIT’s The Engine and The Goose Society, Best and Khatiwada have developed a prototype of a scalable photocatalytic reactor based on the Rice R&D. The first target is zero emission hydrogen production, but the technology could also be adapted for other fuels and chemicals.
“Most photocatalysts struggle on chemical engineering principles such as selectivity, activity, efficiency, and stability, but the antenna reactor improves all these factors by more than an order of magnitude,” says Best, CEO of Syzygy. “We are the first to produce a photocatalytic reactor that can produce chemicals at industrial scale. If this technology takes off, we could reduce millions of tons of CO2 – perhaps even a gigaton or more over time.”
Most photocatalysts struggle on chemical engineering principles such as selectivity, activity, efficiency, and stability, but the antenna reactor improves all these factors by more than an order of magnitude.
In traditional chemical and fuel manufacturing, a feedstock like natural gas is burned to produce heat that induces thermal chemical reactions to create the product. The process is costly and emits gigatons of carbon emissions every year.
Hydrogen is produced using a similar chemical process called steam methane reforming. Typically, natural gas is burned to produce heat of about 1,500°F (about 815°C). Natural gas is also used as part of the reforming processing to extract hydrogen from CH4 molecules. The process takes in natural gas from water and reforms it to produce hydrogen and CO2.
“Steam methane reforming requires high heat and high pressure of about 500 psi, so the equipment must be made of specialized materials like nickel and chrome,” says Best. “It requires very intense engineering.”
Instead of using heat, photocatalysts harvest light to generate energy. Whereas solar cells turn light into electrons, photocatalysts use it to make or break chemical bonds. Japanese researchers in the 1970s pioneered the field with a photocatalyst called Titanium Dioxide that could split water into hydrogen and oxygen with the help of sunlight.
More than 40 years later, photocatalysts have failed to make much headway in the chemical industry. “Traditional photocatalysts like Titanium Dioxide are not great light absorbers,” says Best. “They are highly active only in the UV range and have low stability.”
In the past decade, researchers have begun experimenting with more active photocatalysts made from plasmonic metallic nanoparticles. “Metallic nanoparticles can utilize a broad spectrum of light, including visible wavelengths, enabling chemical reactions in a wide variety of scenarios,” says Best.
The research took a big step forward in 2016 when Rice University Professors Peter Nordlander and Naomi Halas unveiled a promising “antenna reactor” photocatalyst that physically couples plasmonic metallic nanoparticles (the “Antenna”) with smaller nanoparticles made from traditional catalysts (the “Reactor”). Syzygy’s technology is built around the antenna reactor from Nordlander and Halas, who are also Syzygy co-founders and technology advisors.
One of the key concepts behind the antenna reactor is the tunable plasmon, which can tune a catalyst to the wavelength of the received light to create higher efficiency. “The tunable plasmon lets us direct more incoming photons to the catalyst,” says Best.
The larger plasmonic nanoparticles harvest the light and turn those photons into a form of energy called a plasmon, which is essentially a wave of excited electrons. The plasmon interacts with the surfaces of the catalyst nanoparticles to energize them so they can perform chemical reactions.
“The antenna reactor is the most stable, most efficient, and most active photocatalyst to date,” says Best. “It provides high stability against coking and oxidation, and our catalytic activity is even higher than that of a traditional thermal catalyst.”
Because the Syzygy antenna reactor is driven by light instead of heat, the reactor can operate at much lower temperatures. “We can build our reactor from more affordable materials with much lower engineering requirements,” says Best. Other benefits include the ability to start and stop the process near instantaneously instead of powering up over 24 hours, thereby reducing costly downtime for maintenance.
To house the photocatalyst, Syzygy has built a prototype reactor full of mirrors and LEDs. “Our reactor requires electrical engineering for the LEDs, optical engineering for the light, and mechanical engineering for the structural pieces,” says Best. “Then of course there is the chemical engineering, which dictates the temperatures, flow rates, and pressures. The challenge is to make all these different fields of engineering play nice together in a box to maximize efficiency and productivity and keep costs low enough to remain competitive.”
The reactor will be relatively easy to integrate into existing systems, says Best. “Seven of the eight components used in our system are the same as a traditional thermal chemical process. Integrating with compressors, boilers, piping, tubing, and monitoring and purification equipment is pretty easy.”
When Best and Khatiwada, who is Syzygy’s CTO, first cast their net to find their dream technology, they used a framework called Technology, Market, and Impact (TMI). “The framework asks questions about the novelty of the technology, the scientific pedigree and quality of the research, and the scope of what could be built with it,” says Best. “We asked whether people would buy the products and if so, what impact it could have. The goal is to try to kill your idea. When we applied the framework to the antenna reactor, we realized it checked all the boxes: It’s unique, patentable, and predictable, and the impact, measured in emissions reduction, is enormous. We quit our jobs and started Syzygy Plasmonics.”
When we applied the framework to the antenna reactor, we realized it checked all the boxes: It’s unique, patentable, and predictable, and the impact, measured in emissions reduction, is enormous. We quit our jobs and started Syzygy Plasmonics.
The next step was funding. The cofounders attended the Oct 2018 Tough Tech Conference hosted by MIT’s The Engine, an investment group that focuses on challenging new technologies that offer potential for a large impact. “We fell in love with The Engine and the way they support the ecosystem and push for innovative things in ways that others don’t,” says Best. The partners looked for a similar investment group in the Houston area and discovered The Goose Society, which backs the Rice Business Plan Competition.
Best and Khatiwada spent a month fielding tough questions from the potential investors, primarily on the technical side. Everyone agreed there was a market for applying the technology to hydrogen production for photocatalytic steam methane reforming. “Hydrogen is a $100 billion industry with a healthy distributed space and lots of entry points from hydrogen fuel cell vehicles to industrial applications,” says Best.
One of the keys to convincing the investors was to persuade them that the technology could be competitive even in the absence of carbon taxes or regulation. “Even under the current regulatory environment, we believe we can produce zero emission hydrogen at a competitive price with many current practices,” says Best. “If government does provide incentives to switch to low or zero-carbon technologies, that would only strengthen our business case.”
Since Syzygy closed its last fundraise in the second half of 2019, the company has built a new facility in Houston and has grown to 26 employees. Syzygy continues to improve the productivity and efficiency of the reactor and has recently advanced to testing a multi-cell version. “Once we have refined our multi-cell reactor, we can replace a large traditional reactor with many smaller multi-cell reactors,” says Best. “We could scale up to 100s or 1,000s of reactors.” The company expects to achieve a system demo in 2021, followed by field trials and commercial deployment.
Syzygy is already experimenting with using the reactor for other processes. “We have successfully done chemical reactions including CO2 processing -- taking in CO2 and turning it into Syngas,” says Best. “When we go to market, we will take the concentrated CO2 stream from the photocatalytic methane process and feed it into our CO2 reactor to create other products like methanol. We call this ‘Hydrogen Plus,’ because we would be making hydrogen plus another product like methanol – and all with virtually zero emissions released.”
Beyond hydrogen and CO2 processing, Syzygy Plasmonics is looking at other chemical reactions such as ammonia production. “Our plan is to eventually disrupt the entire chemical industry,” says Best. The industry, it seems, may finally be ready for some disruption. “The chemical and fuel industry has remained largely unchanged for the last 100 years, but now I see a desire in the industry to move to low carbon which I didn’t see five or 10 years ago.”