Nonmetallic plasmonic Al-doped W18O49 drives pure CO production from formic acid dehydration

Abstract

As a vital industrial feedstock, carbon monoxide (CO) is widely employed in pharmaceutical, electronic and fine chemical synthesis, yet its efficient production in high purity remains challenging. Here we report a solar-driven route to high-purity CO from formic acid using a nonmetallic plasmonic photocatalyst based on aluminum-doped tungsten oxide (Al-W18O49). Plasmon-derived hot electrons drive the cleavage of C-H in adsorbed formic acid, while a concomitant photothermal effect markedly accelerates the overall kinetics. This synergistic mechanism lowers the apparent activation energy of HCOOH dehydration to 10.5 kJ mol−1, substantially below its thermocatalytic barrier of 80.6 kJ mol−1, and enables a CO production rate of 1.88 mol g−1 h−1 under 1 W cm−2 irradiation. A continuous-flow reactor operated stably for 350 hours, delivering CO at a maximum rate of 2000 L m−2 h−1 under concentrated sunlight. This work develops a practical photocatalytic system for the sustainable production of high-purity CO. This study introduces Al-doped W18O49 nanowires that synergistically utilize plasmonic hot electrons and photothermal effects, enabling solar-driven formic acid dehydration for efficient pure CO generation.