Ultra-Low-Cost Carbon Nanotubes for Stronger Cement and Cost-Competitive Clean Hydrogen

Stanford researchers have developed a catalytic process that co-produces low-carbon hydrogen and carbon nanotubes (CNTs) inexpensively enough to add to ordinary cement without raising its price.

Steam methane reforming produces about 95% of U.S. and 75% of global hydrogen, emitting roughly 9 kg of CO₂ per kilogram. Methane pyrolysis cuts emissions by producing solid carbon, but uses twice the natural gas and, without carbon pricing, is viable only if that carbon can be sold. However, existing carbon markets are too small, and the entire carbon black market would offset only about 5% of reformer-based hydrogen.

The Stanford catalytic co-production method makes CNTs several orders of magnitude cheaper than those available today, turning the global cement market, more than 4 Gt per year, into a practical outlet for pyrolysis carbon. Revenue from the CNTs offsets the added feedstock cost, positioning low-carbon hydrogen to compete with steam reforming. In laboratory tests, cement paste containing the CNTs showed about 22% higher compressive strength and 53% higher tensile strength than an ordinary Portland cement control.

The result is a single process that tackles both the market and technical barriers that have kept methane pyrolysis from scaling.

Stage of Development:Proof of concept
CNT and hydrogen co-production has been demonstrated in a bench-scale reactor, and cement paste samples tested after a 28-day cure show strength gains.