Energy-oriented utilization from organic wastewater: Directional photoelectrocatalytic conversion of phenol to C1 fuels

Abstract

To solve the problems of energy consumption, carbon emissions and pollution simultaneously, the directional conversion of phenol to hydrocarbon fuels through a pathway of “phenol → CO2 → HCO3–→HCOOH” was explored, with self-supplied CO2 as both carbon-based transition carrier and electron acceptor. In this economic approach, photoelectrocatalytic (PEC) deep mineralization of phenol was realized on the photoanode to provide CO2, together with the waste electrons from mineralization, was PEC converted into formate as the major liquid product on photocathode under an applied potential of 3 V and simulated sunlight. The total carbon utilization efficiency of phenol to hydrocarbons is 6.76%, and the conversion efficiency of formic acid is as high as 94.8% within 8 h PEC reaction. The integrated cell achieved the recovery of 2.75% waste electrons from phenol oxidation to produce liquid fuel. This work provides a promising “carbon neutral” strategy, which is important for realizing pollutant resource utilization and alleviating energy shortage.