A review of methanol photoreforming: elucidating the mechanisms, photocatalysts and recent advancement strategies

Methanol photoreforming is an emerging and promising technology in harnessing solar energy to produce hydrogen as well as value-added by-products including formaldehyde (HCHO), formic acid (HCOOH), and methyl formate (HCOOCH₃). Unlike photocatalytic water splitting, methanol (CH₃OH) photoreforming has significantly lower reaction energy and clean water demand. Besides, methanol as the organic substrate with availability from industrial waste streams allows the potential collaboration of photoreforming plants with relevant waste treatment facilities. In harmonization with the expeditious research progress in methanol photoreforming, this work provides an extensive review from the perspectives of reaction mechanisms and photocatalyst systems, as well as modification techniques including co-catalyst loading and heterojunctions or Z-schemes formation in endowing performance enhancement. Ultimately, this work aims to provide insight, notably into the rational engineering of photocatalytic materials, which would spearhead future development. The prospect and challenges in this field are put forward to empower collective efforts in paving a sustainable and efficient technology.