Electrostatic Field Regulate Interfacial Hole Transfer for Photocatalytic Valorization of Biopolyols

Abstract

Photocatalysis has shown power in the valorization of biomass while controlling the selectivity is a long-standing goal and challenge, especially for the complex and reactive bio-polyols. The selectivity control of photocatalytic biopolyols reforming to formic acid (FA) or CO is realized via engineering the electrostatic field on TiO₂ semiconductor. The electrostatic field is generated by surface modification with anion adsorbates, which can alter the trap states of photoexcited holes and regulate interfacial hole transfer to the surface-bound species, thereby strongly affecting photocatalytic activity. Taking formic acid dehydration as an example, a shallow trap of photoexcited holes on pristine TiO₂ favors the dehydration of FA to CO, while a deep trap of photoexcited holes after introduced anion adsorbates makes FA stable. Based on this result, the selectivity is successfully tuned in the photocatalytic oxidation of biopolyols via controlling electrostatic field. A wide range of biopolyols can be selectively converted into FA or CO. This work presents an effective strategy to manipulate reaction pathways via generating electric field.