Water microdroplet chemistry is contentious, here’s why

Droplets

Source: © Science Photo Library

Are water microdroplets chemical dynamos or are their apparent effects experimental artefacts? Rebecca Trager investigates

When a team led by Stanford University’s Richard Zare  announced in 2019 that sprays of microscopic water droplets spontaneously produce hydrogen peroxide  it attracted both excitement and scepticism. These days Zare is doubling down, arguing that many applications for catalysis – including nitrogen fixing, converting methane to methanol and transforming carbon dioxide into valuable chemicals – can be addressed with water microdroplets.