Light, Heat and Electricity Integrated Energy Conversion System: Photothermal-Assisted Co-Electrolysis of CO2 and Methanol

Abstract

Strategy that can design powerful photothermal-catalysts to achieve photothermal-effect assisted coupling-catalysis is much desired for the improvement of energy conversion efficiency and redox product value in CO₂ electroreduction system. Herein, a kind of bifunctional viologen-containing covalent organic framework (Ni-2CBpy²⁺ -COF) has been prepared and successfully applied in photothermal-assisted co-electrolysis of CO₂ and methanol. Specifically, the FE_CO (cathode) and FE_HCOOH (anode) for Ni-2CBpy²⁺ -COF can reach up to ≈100 % at 1.9 V with ≈31.5 % saved overall electricity-consumption when the anodic oxygen evolution reaction (OER) is replaced by methanol oxidation. The superior performance could be attributed to the cyclic diquats in Ni-2CBpy²⁺ -COF that enhance the photothermal effect (ΔT=49.1 °C) to accelerate faster charge transfer between catalyst and immediate species as well as higher selectivity towards desired products as revealed by DFT calculations and characterizations.

Keywords: Bifunctional Catalysts; Co-Electrolysis of CO2 and Methanol; Photothermal Conversion Effect; Photothermal-Assisted.