Widely used for paper bleaching, water treatment, and other applications, hydrogen peroxide is typically made in a multi-step, energy-intensive process that requires production of large quantities that must be shipped and stored in a highly concentrated form.

Palladium particle (red) shown supported on tin oxide (green) before heat treatment. Image source: Lehigh University. Researchers from the UK and the U.S. have developed a method of producing hydrogen peroxide on demand through a one-step process. The method enables dilute H₂O₂ to be made directly from hydrogen and oxygen in small quantities on-site. Doing so may make it more accessible to underdeveloped regions of the world, where it could be used to purify water.

The researchers previously developed a state-of-the-art catalyst made from palladium and gold nanoparticles that helped to create H₂O₂ from hydrogen and oxygen. In search of an alternative to gold, the team replaced the metal with readily available tin, cobalt, nickel, gallium, indium, or zinc. The new catalyst can be made without the need to pre-treat the catalyst support with nitric acid, which is a requirement of gold-palladium alloys.

The new process overcomes a longstanding challenge to the catalytic production of H₂O₂, namely the tendency of the catalyst to quickly decompose the product into water soon after it has been made. The group deposited a palladium-tin mixture onto a titanium dioxide (TiO2) support and observed that some of the tin spread out to form a thin tin oxide layer over the TiO2 while the remainder was consumed in making palladium-tin alloy particles. The researchers developed a three-step heat treatment process that induced the secondary tin-oxide support layer to encapsulate the small palladium-rich particles. This served to muzzle the nuisance particles and prevent them from catalyzing the hydrogenation and decomposition of the H₂O₂. Palladium-tin catalysts supported on titanium dioxide were demonstrated to switch off the hydrogenation of H₂O₂ and give an overall selectivity to the desired product of more than 95 percent.